From 6543d88cbe5cea2596bae47f6bfd26c3048aab83 Mon Sep 17 00:00:00 2001
From: Ivan <8611739+IRBorisov@users.noreply.github.com>
Date: Thu, 23 Jan 2025 19:41:31 +0300
Subject: [PATCH] F: Implement react-query pt3

---
 .../frontend/src/app/ApplicationLayout.tsx    |   2 +-
 rsconcept/frontend/src/app/GlobalDialogs.tsx  |   2 +-
 .../src/{context => app}/GlobalOssContext.tsx |  64 +-
 .../frontend/src/app/GlobalProviders.tsx      |   5 +-
 .../src/app/Navigation/Navigation.tsx         |   6 +-
 .../src/app/Navigation/NavigationButton.tsx   |   2 +-
 .../Navigation}/NavigationContext.tsx         |   0
 .../src/app/Navigation/UserDropdown.tsx       |   2 +-
 .../frontend/src/app/Navigation/UserMenu.tsx  |   2 +-
 .../frontend/src/backend/apiTransport.ts      |   2 +-
 rsconcept/frontend/src/backend/auth/api.ts    |  18 +-
 .../src/backend/auth/useChangePassword.tsx    |   9 +-
 .../frontend/src/backend/auth/useLogin.tsx    |  11 +-
 .../frontend/src/backend/auth/useLogout.tsx   |   4 +-
 .../backend/auth/useRequestPasswordReset.tsx  |   5 +-
 .../src/backend/auth/useResetPassword.tsx     |  16 +-
 .../{apiConfiguration.ts => axiosInstance.ts} |   0
 rsconcept/frontend/src/backend/cctext.ts      |  28 -
 rsconcept/frontend/src/backend/cctext/api.ts  |  26 +
 .../src/backend/cctext/useGenerateLexeme.tsx  |  19 +
 .../src/backend/cctext/useInflectText.tsx     |  19 +
 .../backend/cctext/useIsProcessingCctext.tsx  |   8 +
 .../src/backend/cctext/useParseText.tsx       |  17 +
 .../frontend/src/backend/configuration.ts     |   9 +
 rsconcept/frontend/src/backend/library.ts     | 117 ---
 rsconcept/frontend/src/backend/library/api.ts | 137 ++++
 .../backend/library/useApplyLibraryFilter.tsx |  47 ++
 .../src/backend/library/useCloneItem.tsx      |  21 +
 .../src/backend/library/useCreateItem.tsx     |  24 +
 .../src/backend/library/useDeleteItem.tsx     |  26 +
 .../src/backend/library/useFolders.tsx        |  17 +
 .../library/useIsProcessingLibrary.tsx        |   8 +
 .../src/backend/library/useLibrary.tsx        |  21 +
 .../src/backend/library/useRenameLocation.tsx |  18 +
 .../backend/library/useSetAccessPolicy.tsx    |  41 ++
 .../src/backend/library/useSetEditors.tsx     |  39 +
 .../src/backend/library/useSetLocation.tsx    |  41 ++
 .../src/backend/library/useSetOwner.tsx       |  42 ++
 .../src/backend/library/useTemplates.tsx      |  17 +
 .../src/backend/library/useUpdateItem.tsx     |  34 +
 .../backend/library/useUpdateTimestamp.tsx    |  17 +
 .../src/backend/library/useVersionCreate.tsx  |  30 +
 .../src/backend/library/useVersionDelete.tsx  |  33 +
 .../src/backend/library/useVersionRestore.tsx |  29 +
 .../src/backend/library/useVersionUpdate.tsx  |  38 +
 rsconcept/frontend/src/backend/oss.ts         |  92 ---
 rsconcept/frontend/src/backend/oss/api.ts     | 148 ++++
 .../src/backend/oss/useFindPredecessor.tsx    |  19 +
 .../src/backend/oss/useInputCreate.tsx        |  28 +
 .../src/backend/oss/useInputUpdate.tsx        |  27 +
 .../src/backend/oss/useIsProcessingOss.tsx    |  11 +
 rsconcept/frontend/src/backend/oss/useOSS.tsx |  47 ++
 .../src/backend/oss/useOperationCreate.tsx    |  30 +
 .../src/backend/oss/useOperationDelete.tsx    |  27 +
 .../src/backend/oss/useOperationExecute.tsx   |  27 +
 .../src/backend/oss/useOperationUpdate.tsx    |  27 +
 .../backend/oss/useRelocateConstituents.tsx   |  27 +
 .../src/backend/oss/useUpdatePositions.tsx    |  25 +
 rsconcept/frontend/src/backend/queryClient.ts |   6 +-
 rsconcept/frontend/src/backend/rsform/api.ts  | 191 +++++
 .../backend/rsform/useCheckConstituenta.tsx   |  26 +
 .../src/backend/rsform/useCstCreate.tsx       |  31 +
 .../src/backend/rsform/useCstDelete.tsx       |  30 +
 .../src/backend/rsform/useCstMove.tsx         |  29 +
 .../src/backend/rsform/useCstRename.tsx       |  31 +
 .../src/backend/rsform/useCstSubstitute.tsx   |  30 +
 .../src/backend/rsform/useCstUpdate.tsx       |  33 +
 .../src/backend/rsform/useDownloadRSForm.tsx  |  21 +
 .../src/backend/rsform/useInlineSynthesis.tsx |  31 +
 .../backend/rsform/useIsProcessingRSForm.tsx  |  11 +
 .../backend/rsform/useProduceStructure.tsx    |  31 +
 .../frontend/src/backend/rsform/useRSForm.tsx |  34 +
 .../src/backend/rsform/useRSForms.tsx         |  23 +
 .../src/backend/rsform/useResetAliases.tsx    |  26 +
 .../src/backend/rsform/useRestoreOrder.tsx    |  25 +
 .../src/backend/rsform/useUploadTRS.tsx       |  28 +
 rsconcept/frontend/src/backend/rsforms.ts     | 158 ----
 rsconcept/frontend/src/backend/users/api.ts   |  11 +-
 .../frontend/src/backend/users/useSignup.tsx  |  13 +-
 .../src/backend/users/useUpdateProfile.tsx    |  11 +-
 .../frontend/src/backend/users/useUsers.tsx   |   3 +-
 rsconcept/frontend/src/backend/versions.ts    |  30 -
 .../src/components/RSInput/RSInput.tsx        |   2 +-
 .../src/components/info/BadgeGrammeme.tsx     |   2 +-
 .../src/components/info/InfoCstStatus.tsx     |   2 +-
 .../src/components/info/InfoError.tsx         |   2 +-
 .../src/components/select/PickSchema.tsx      |   4 -
 .../src/components/select/SelectLocation.tsx  |  11 +-
 .../select/SelectLocationContext.tsx          |   4 -
 .../frontend/src/components/ui/Checkbox.tsx   |   4 +-
 .../src/components/ui/CheckboxTristate.tsx    |   4 +-
 .../frontend/src/components/ui/PrettyJSON.tsx |   3 +-
 .../src/components/wrap/ExpectedAnonymous.tsx |   2 +-
 .../frontend/src/context/LibraryContext.tsx   | 322 ---------
 rsconcept/frontend/src/context/OssContext.tsx | 390 ----------
 .../frontend/src/context/RSFormContext.tsx    | 592 ---------------
 .../src/dialogs/DlgChangeInputSchema.tsx      |   6 +-
 .../src/dialogs/DlgCloneLibraryItem.tsx       |  16 +-
 .../src/dialogs/DlgCreateCst/DlgCreateCst.tsx |   7 +-
 .../dialogs/DlgCreateCst/FormCreateCst.tsx    |   7 +-
 .../DlgCreateOperation/DlgCreateOperation.tsx |  19 +-
 .../DlgCreateOperation/TabInputOperation.tsx  |   6 +-
 .../frontend/src/dialogs/DlgCreateVersion.tsx |  16 +-
 .../dialogs/DlgCstTemplate/DlgCstTemplate.tsx |  27 +-
 .../dialogs/DlgCstTemplate/TabArguments.tsx   |   6 +-
 .../dialogs/DlgCstTemplate/TabTemplate.tsx    |   4 +-
 .../DlgEditOperation/DlgEditOperation.tsx     |  48 +-
 .../dialogs/DlgEditOperation/TabSynthesis.tsx |  40 +-
 .../TabSyntacticReference.tsx                 |   2 +-
 .../DlgEditWordForms/DlgEditWordForms.tsx     |  34 +-
 .../DlgInlineSynthesis/DlgInlineSynthesis.tsx |  18 +-
 .../dialogs/DlgInlineSynthesis/TabSchema.tsx  |  11 +-
 .../src/dialogs/DlgRelocateConstituents.tsx   |  26 +-
 .../frontend/src/dialogs/DlgRenameCst.tsx     |   7 +-
 .../frontend/src/dialogs/DlgSubstituteCst.tsx |   6 +-
 .../frontend/src/dialogs/DlgUploadRSForm.tsx  |  12 +-
 .../src/hooks/useCheckConstituenta.ts         |  40 --
 .../frontend/src/hooks/useConceptText.ts      |  56 --
 rsconcept/frontend/src/hooks/useOssDetails.ts |  66 --
 .../frontend/src/hooks/useRSFormCache.ts      |  56 --
 .../frontend/src/hooks/useRSFormDetails.ts    |  61 --
 rsconcept/frontend/src/hooks/useRSParse.ts    |  32 +
 rsconcept/frontend/src/models/language.ts     |  13 -
 rsconcept/frontend/src/models/library.ts      |  44 --
 rsconcept/frontend/src/models/oss.ts          |  71 +-
 rsconcept/frontend/src/models/rsform.ts       |  91 +--
 rsconcept/frontend/src/models/user.ts         |  14 -
 .../pages/CreateItemPage/FormCreateItem.tsx   |  22 +-
 rsconcept/frontend/src/pages/HomePage.tsx     |   2 +-
 .../src/pages/LibraryPage/LibraryPage.tsx     |  47 +-
 .../pages/LibraryPage/TableLibraryItems.tsx   |   2 +-
 .../src/pages/LibraryPage/ToolbarSearch.tsx   |   2 +-
 .../pages/LibraryPage/ViewSideLocation.tsx    |   8 +-
 rsconcept/frontend/src/pages/LoginPage.tsx    |   2 +-
 .../src/pages/ManualsPage/ManualsPage.tsx     |   2 +-
 .../OssPage}/DlgChangeLocation.tsx            |  10 +-
 .../OssPage/EditorOssCard/EditorOssCard.tsx   |   6 +-
 .../pages/OssPage/EditorOssCard/FormOSS.tsx   |  16 +-
 .../pages/OssPage/EditorOssGraph/OssFlow.tsx  |  18 +-
 .../src/pages/OssPage/MenuOssTabs.tsx         |   8 +-
 .../src/pages/OssPage/OssEditContext.tsx      |  99 ++-
 .../frontend/src/pages/OssPage/OssPage.tsx    |  13 +-
 .../frontend/src/pages/OssPage/OssTabs.tsx    |  13 +-
 .../frontend/src/pages/PasswordChangePage.tsx |   2 +-
 .../EditorConstituenta/ControlsOverlay.tsx    |   2 +-
 .../EditorConstituenta/FormConstituenta.tsx   |  41 +-
 .../EditorRSExpression/EditorRSExpression.tsx |  19 +-
 .../ToolbarRSExpression.tsx                   |   6 +-
 .../EditorRSFormCard/EditorLibraryItem.tsx    |   2 +-
 .../EditorRSFormCard/EditorRSFormCard.tsx     |   6 +-
 .../EditorRSFormCard/FormRSForm.tsx           |  15 +-
 .../EditorTermGraph/SchemasGuide.tsx          |   6 +-
 .../src/pages/RSFormPage/MenuRSTabs.tsx       |  16 +-
 .../src/pages/RSFormPage/RSEditContext.tsx    | 677 +++++++++---------
 .../frontend/src/pages/RSFormPage/RSTabs.tsx  |  27 +-
 .../frontend/src/pages/RSFormPage/index.tsx   |   2 +-
 .../src/pages/RegisterPage/FormSignup.tsx     |   2 +-
 .../pages/UserProfilePage/EditorPassword.tsx  |   2 +-
 .../pages/UserProfilePage/EditorProfile.tsx   |   2 +-
 rsconcept/frontend/src/stores/dialogs.ts      |   2 +-
 .../frontend/src/stores/librarySearch.ts      |   2 +-
 rsconcept/frontend/src/utils/codemirror.ts    |   2 +-
 162 files changed, 2667 insertions(+), 3113 deletions(-)
 rename rsconcept/frontend/src/{context => app}/GlobalOssContext.tsx (51%)
 rename rsconcept/frontend/src/{context => app/Navigation}/NavigationContext.tsx (100%)
 rename rsconcept/frontend/src/backend/{apiConfiguration.ts => axiosInstance.ts} (100%)
 delete mode 100644 rsconcept/frontend/src/backend/cctext.ts
 create mode 100644 rsconcept/frontend/src/backend/cctext/api.ts
 create mode 100644 rsconcept/frontend/src/backend/cctext/useGenerateLexeme.tsx
 create mode 100644 rsconcept/frontend/src/backend/cctext/useInflectText.tsx
 create mode 100644 rsconcept/frontend/src/backend/cctext/useIsProcessingCctext.tsx
 create mode 100644 rsconcept/frontend/src/backend/cctext/useParseText.tsx
 create mode 100644 rsconcept/frontend/src/backend/configuration.ts
 delete mode 100644 rsconcept/frontend/src/backend/library.ts
 create mode 100644 rsconcept/frontend/src/backend/library/api.ts
 create mode 100644 rsconcept/frontend/src/backend/library/useApplyLibraryFilter.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useCloneItem.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useCreateItem.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useDeleteItem.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useFolders.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useIsProcessingLibrary.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useLibrary.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useRenameLocation.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useSetAccessPolicy.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useSetEditors.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useSetLocation.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useSetOwner.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useTemplates.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useUpdateItem.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useUpdateTimestamp.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useVersionCreate.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useVersionDelete.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useVersionRestore.tsx
 create mode 100644 rsconcept/frontend/src/backend/library/useVersionUpdate.tsx
 delete mode 100644 rsconcept/frontend/src/backend/oss.ts
 create mode 100644 rsconcept/frontend/src/backend/oss/api.ts
 create mode 100644 rsconcept/frontend/src/backend/oss/useFindPredecessor.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useInputCreate.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useInputUpdate.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useIsProcessingOss.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useOSS.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useOperationCreate.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useOperationDelete.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useOperationExecute.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useOperationUpdate.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useRelocateConstituents.tsx
 create mode 100644 rsconcept/frontend/src/backend/oss/useUpdatePositions.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/api.ts
 create mode 100644 rsconcept/frontend/src/backend/rsform/useCheckConstituenta.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useCstCreate.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useCstDelete.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useCstMove.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useCstRename.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useCstSubstitute.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useCstUpdate.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useDownloadRSForm.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useInlineSynthesis.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useIsProcessingRSForm.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useProduceStructure.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useRSForm.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useRSForms.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useResetAliases.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useRestoreOrder.tsx
 create mode 100644 rsconcept/frontend/src/backend/rsform/useUploadTRS.tsx
 delete mode 100644 rsconcept/frontend/src/backend/rsforms.ts
 delete mode 100644 rsconcept/frontend/src/backend/versions.ts
 delete mode 100644 rsconcept/frontend/src/context/LibraryContext.tsx
 delete mode 100644 rsconcept/frontend/src/context/OssContext.tsx
 delete mode 100644 rsconcept/frontend/src/context/RSFormContext.tsx
 delete mode 100644 rsconcept/frontend/src/hooks/useCheckConstituenta.ts
 delete mode 100644 rsconcept/frontend/src/hooks/useConceptText.ts
 delete mode 100644 rsconcept/frontend/src/hooks/useOssDetails.ts
 delete mode 100644 rsconcept/frontend/src/hooks/useRSFormCache.ts
 delete mode 100644 rsconcept/frontend/src/hooks/useRSFormDetails.ts
 create mode 100644 rsconcept/frontend/src/hooks/useRSParse.ts
 rename rsconcept/frontend/src/{dialogs => pages/OssPage}/DlgChangeLocation.tsx (90%)

diff --git a/rsconcept/frontend/src/app/ApplicationLayout.tsx b/rsconcept/frontend/src/app/ApplicationLayout.tsx
index ea527ea1..dc506950 100644
--- a/rsconcept/frontend/src/app/ApplicationLayout.tsx
+++ b/rsconcept/frontend/src/app/ApplicationLayout.tsx
@@ -5,7 +5,7 @@ import ConceptToaster from '@/app/ConceptToaster';
 import Footer from '@/app/Footer';
 import Navigation from '@/app/Navigation';
 import Loader from '@/components/ui/Loader';
-import { NavigationState } from '@/context/NavigationContext';
+import { NavigationState } from '@/app/Navigation/NavigationContext';
 import { useAppLayoutStore, useMainHeight, useViewportHeight } from '@/stores/appLayout';
 import { globals } from '@/utils/constants';
 
diff --git a/rsconcept/frontend/src/app/GlobalDialogs.tsx b/rsconcept/frontend/src/app/GlobalDialogs.tsx
index a20ce7db..25560b80 100644
--- a/rsconcept/frontend/src/app/GlobalDialogs.tsx
+++ b/rsconcept/frontend/src/app/GlobalDialogs.tsx
@@ -1,7 +1,7 @@
 'use client';
 
 import DlgChangeInputSchema from '@/dialogs/DlgChangeInputSchema';
-import DlgChangeLocation from '@/dialogs/DlgChangeLocation';
+import DlgChangeLocation from '@/pages/OssPage/DlgChangeLocation';
 import DlgCloneLibraryItem from '@/dialogs/DlgCloneLibraryItem';
 import DlgCreateCst from '@/dialogs/DlgCreateCst';
 import DlgCreateOperation from '@/dialogs/DlgCreateOperation';
diff --git a/rsconcept/frontend/src/context/GlobalOssContext.tsx b/rsconcept/frontend/src/app/GlobalOssContext.tsx
similarity index 51%
rename from rsconcept/frontend/src/context/GlobalOssContext.tsx
rename to rsconcept/frontend/src/app/GlobalOssContext.tsx
index fd803c88..30a40e87 100644
--- a/rsconcept/frontend/src/context/GlobalOssContext.tsx
+++ b/rsconcept/frontend/src/app/GlobalOssContext.tsx
@@ -2,24 +2,22 @@
 
 import { createContext, useCallback, useContext, useState } from 'react';
 
+import { useOss, useOssInvalidate, useOssUpdate } from '@/backend/oss/useOSS';
 import { ErrorData } from '@/components/info/InfoError';
-import useOssDetails from '@/hooks/useOssDetails';
 import { LibraryItemID } from '@/models/library';
 import { IOperationSchema, IOperationSchemaData } from '@/models/oss';
 import { contextOutsideScope } from '@/utils/labels';
 
 interface IGlobalOssContext {
   schema: IOperationSchema | undefined;
-  setID: (id: string | undefined) => void;
+  setID: (id: LibraryItemID | undefined) => void;
   setData: (data: IOperationSchemaData) => void;
   loading: boolean;
   loadingError: ErrorData;
-  isValid: boolean;
 
-  invalidate: () => void;
+  invalidate: () => Promise<void>;
   invalidateItem: (target: LibraryItemID) => void;
   partialUpdate: (data: Partial<IOperationSchema>) => void;
-  reload: (callback?: () => void) => void;
 }
 
 const GlobalOssContext = createContext<IGlobalOssContext | null>(null);
@@ -32,58 +30,18 @@ export const useGlobalOss = (): IGlobalOssContext => {
 };
 
 export const GlobalOssState = ({ children }: React.PropsWithChildren) => {
-  const [isValid, setIsValid] = useState(true);
-  const [ossID, setIdInternal] = useState<string | undefined>(undefined);
-  const {
-    schema: schema, // prettier: split lines
-    error: loadingError,
-    setSchema: setDataInternal,
-    loading: loading,
-    reload: reloadInternal,
-    partialUpdate
-  } = useOssDetails({ target: ossID });
-
-  const reload = useCallback(
-    (callback?: () => void) => {
-      reloadInternal(undefined, () => {
-        setIsValid(true);
-        callback?.();
-      });
-    },
-    [reloadInternal]
-  );
-
-  const setData = useCallback(
-    (data: IOperationSchemaData) => {
-      setDataInternal(data);
-      setIsValid(true);
-    },
-    [setDataInternal]
-  );
-
-  const setID = useCallback(
-    (id: string | undefined) => {
-      setIdInternal(prev => {
-        if (prev === id && !isValid) {
-          reload();
-        }
-        return id;
-      });
-    },
-    [setIdInternal, isValid, reload]
-  );
-
-  const invalidate = useCallback(() => {
-    setIsValid(false);
-  }, []);
+  const [ossID, setID] = useState<LibraryItemID | undefined>(undefined);
+  const { schema: schema, error: loadingError, isLoading: loading } = useOss({ itemID: ossID });
+  const { update, partialUpdate } = useOssUpdate({ itemID: ossID });
+  const { invalidate } = useOssInvalidate({ itemID: ossID });
 
   const invalidateItem = useCallback(
     (target: LibraryItemID) => {
       if (schema?.schemas.includes(target)) {
-        setIsValid(false);
+        invalidate().catch(console.error);
       }
     },
-    [schema]
+    [invalidate, schema]
   );
 
   return (
@@ -91,12 +49,10 @@ export const GlobalOssState = ({ children }: React.PropsWithChildren) => {
       value={{
         schema,
         setID,
-        setData,
+        setData: update,
         loading,
         loadingError,
-        reload,
         partialUpdate,
-        isValid,
         invalidateItem,
         invalidate
       }}
diff --git a/rsconcept/frontend/src/app/GlobalProviders.tsx b/rsconcept/frontend/src/app/GlobalProviders.tsx
index 2dd21953..9785495a 100644
--- a/rsconcept/frontend/src/app/GlobalProviders.tsx
+++ b/rsconcept/frontend/src/app/GlobalProviders.tsx
@@ -6,8 +6,7 @@ import { ErrorBoundary } from 'react-error-boundary';
 import { IntlProvider } from 'react-intl';
 
 import { queryClient } from '@/backend/queryClient';
-import { GlobalOssState } from '@/context/GlobalOssContext';
-import { LibraryState } from '@/context/LibraryContext';
+import { GlobalOssState } from '@/app/GlobalOssContext';
 
 import ErrorFallback from './ErrorFallback';
 
@@ -32,14 +31,12 @@ function GlobalProviders({ children }: React.PropsWithChildren) {
   >
   <IntlProvider locale='ru' defaultLocale='ru'>
   <QueryClientProvider client={queryClient}>
-  <LibraryState>
   <GlobalOssState>
   
     <ReactQueryDevtools initialIsOpen={false} />
     {children}
   
   </GlobalOssState>
-  </LibraryState>
   </QueryClientProvider>
   </IntlProvider>
   </ErrorBoundary>);
diff --git a/rsconcept/frontend/src/app/Navigation/Navigation.tsx b/rsconcept/frontend/src/app/Navigation/Navigation.tsx
index 571e7a87..b39f15e6 100644
--- a/rsconcept/frontend/src/app/Navigation/Navigation.tsx
+++ b/rsconcept/frontend/src/app/Navigation/Navigation.tsx
@@ -2,7 +2,7 @@ import clsx from 'clsx';
 
 import { IconLibrary2, IconManuals, IconNewItem2 } from '@/components/Icons';
 import { CProps } from '@/components/props';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import useWindowSize from '@/hooks/useWindowSize';
 import { useAppLayoutStore } from '@/stores/appLayout';
 import { PARAMETER } from '@/utils/constants';
@@ -27,7 +27,7 @@ function Navigation() {
   return (
     <nav
       className={clsx(
-        'z-navigation', // prettier: split lines
+        'z-navigation', //
         'sticky top-0 left-0 right-0',
         'select-none',
         'bg-prim-100'
@@ -36,7 +36,7 @@ function Navigation() {
       <ToggleNavigation />
       <div
         className={clsx(
-          'pl-2 pr-[1.5rem] sm:pr-[0.9rem] h-[3rem]', // prettier: split lines
+          'pl-2 pr-[1.5rem] sm:pr-[0.9rem] h-[3rem]', //
           'flex',
           'cc-shadow-border'
         )}
diff --git a/rsconcept/frontend/src/app/Navigation/NavigationButton.tsx b/rsconcept/frontend/src/app/Navigation/NavigationButton.tsx
index b16970d7..93eab2b8 100644
--- a/rsconcept/frontend/src/app/Navigation/NavigationButton.tsx
+++ b/rsconcept/frontend/src/app/Navigation/NavigationButton.tsx
@@ -29,7 +29,7 @@ function NavigationButton({
       data-tooltip-hidden={hideTitle}
       onClick={onClick}
       className={clsx(
-        'mr-1 h-full', // prettier: split lines
+        'mr-1 h-full', //
         'flex items-center gap-1',
         'clr-btn-nav cc-animate-color duration-500',
         'rounded-xl',
diff --git a/rsconcept/frontend/src/context/NavigationContext.tsx b/rsconcept/frontend/src/app/Navigation/NavigationContext.tsx
similarity index 100%
rename from rsconcept/frontend/src/context/NavigationContext.tsx
rename to rsconcept/frontend/src/app/Navigation/NavigationContext.tsx
diff --git a/rsconcept/frontend/src/app/Navigation/UserDropdown.tsx b/rsconcept/frontend/src/app/Navigation/UserDropdown.tsx
index 16b77812..6924d207 100644
--- a/rsconcept/frontend/src/app/Navigation/UserDropdown.tsx
+++ b/rsconcept/frontend/src/app/Navigation/UserDropdown.tsx
@@ -17,7 +17,7 @@ import {
 import { CProps } from '@/components/props';
 import Dropdown from '@/components/ui/Dropdown';
 import DropdownButton from '@/components/ui/DropdownButton';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { usePreferencesStore } from '@/stores/preferences';
 
 import { urls } from '../urls';
diff --git a/rsconcept/frontend/src/app/Navigation/UserMenu.tsx b/rsconcept/frontend/src/app/Navigation/UserMenu.tsx
index a36499aa..f4ea4b79 100644
--- a/rsconcept/frontend/src/app/Navigation/UserMenu.tsx
+++ b/rsconcept/frontend/src/app/Navigation/UserMenu.tsx
@@ -1,7 +1,7 @@
 import { Suspense } from 'react';
 
 import Loader from '@/components/ui/Loader';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import useDropdown from '@/hooks/useDropdown';
 
 import { urls } from '../urls';
diff --git a/rsconcept/frontend/src/backend/apiTransport.ts b/rsconcept/frontend/src/backend/apiTransport.ts
index af21e549..6916e3c3 100644
--- a/rsconcept/frontend/src/backend/apiTransport.ts
+++ b/rsconcept/frontend/src/backend/apiTransport.ts
@@ -7,7 +7,7 @@ import { toast } from 'react-toastify';
 import { ErrorData } from '@/components/info/InfoError';
 import { extractErrorMessage } from '@/utils/utils';
 
-import { axiosInstance } from './apiConfiguration';
+import { axiosInstance } from './axiosInstance';
 
 // ================ Data transfer types ================
 export type DataCallback<ResponseData = undefined> = (data: ResponseData) => void;
diff --git a/rsconcept/frontend/src/backend/auth/api.ts b/rsconcept/frontend/src/backend/auth/api.ts
index 4d543c1d..340d4e8a 100644
--- a/rsconcept/frontend/src/backend/auth/api.ts
+++ b/rsconcept/frontend/src/backend/auth/api.ts
@@ -1,8 +1,8 @@
 import { queryOptions } from '@tanstack/react-query';
 
-import { ICurrentUser, IUser } from '@/models/user';
-
-import { axiosInstance } from '../apiConfiguration';
+import { axiosInstance } from '@/backend/axiosInstance';
+import { DELAYS } from '@/backend/configuration';
+import { ICurrentUser } from '@/models/user';
 
 /**
  * Represents login data, used to authenticate users.
@@ -23,7 +23,9 @@ export interface IChangePasswordDTO {
 /**
  * Represents password reset request data.
  */
-export interface IRequestPasswordDTO extends Pick<IUser, 'email'> {}
+export interface IRequestPasswordDTO {
+  email: string;
+}
 
 /**
  * Represents password reset data.
@@ -36,7 +38,9 @@ export interface IResetPasswordDTO {
 /**
  * Represents password token data.
  */
-export interface IPasswordTokenDTO extends Pick<IResetPasswordDTO, 'token'> {}
+export interface IPasswordTokenDTO {
+  token: string;
+}
 
 /**
  * Authentication API.
@@ -47,14 +51,14 @@ export const authApi = {
   getAuthQueryOptions: () => {
     return queryOptions({
       queryKey: [authApi.baseKey, 'user'],
+      staleTime: DELAYS.staleLong,
       queryFn: meta =>
         axiosInstance
           .get<ICurrentUser>('/users/api/auth', {
             signal: meta.signal
           })
           .then(response => (response.data.id === null ? null : response.data)),
-      placeholderData: null,
-      staleTime: 24 * 60 * 60 * 1000
+      placeholderData: null
     });
   },
 
diff --git a/rsconcept/frontend/src/backend/auth/useChangePassword.tsx b/rsconcept/frontend/src/backend/auth/useChangePassword.tsx
index 79c00fc5..39f9af58 100644
--- a/rsconcept/frontend/src/backend/auth/useChangePassword.tsx
+++ b/rsconcept/frontend/src/backend/auth/useChangePassword.tsx
@@ -3,14 +3,17 @@ import { useMutation, useQueryClient } from '@tanstack/react-query';
 import { authApi, IChangePasswordDTO } from './api';
 
 export const useChangePassword = () => {
-  const queryClient = useQueryClient();
+  const client = useQueryClient();
   const mutation = useMutation({
     mutationKey: ['change-password'],
     mutationFn: authApi.changePassword,
-    onSettled: () => queryClient.invalidateQueries({ queryKey: [authApi.baseKey] })
+    onSettled: async () => await client.invalidateQueries({ queryKey: [authApi.baseKey] })
   });
   return {
-    changePassword: (data: IChangePasswordDTO, onSuccess?: () => void) => mutation.mutate(data, { onSuccess }),
+    changePassword: (
+      data: IChangePasswordDTO, //
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess }),
     isPending: mutation.isPending,
     error: mutation.error,
     reset: mutation.reset
diff --git a/rsconcept/frontend/src/backend/auth/useLogin.tsx b/rsconcept/frontend/src/backend/auth/useLogin.tsx
index 9924a2ad..a61beb2a 100644
--- a/rsconcept/frontend/src/backend/auth/useLogin.tsx
+++ b/rsconcept/frontend/src/backend/auth/useLogin.tsx
@@ -3,15 +3,18 @@ import { useMutation, useQueryClient } from '@tanstack/react-query';
 import { authApi } from './api';
 
 export const useLogin = () => {
-  const queryClient = useQueryClient();
+  const client = useQueryClient();
   const mutation = useMutation({
     mutationKey: ['login'],
     mutationFn: authApi.login,
-    onSettled: () => queryClient.invalidateQueries({ queryKey: [authApi.baseKey] })
+    onSettled: async () => await client.invalidateQueries({ queryKey: [authApi.baseKey] })
   });
   return {
-    login: (username: string, password: string, onSuccess?: () => void) =>
-      mutation.mutate({ username, password }, { onSuccess }),
+    login: (
+      username: string, //
+      password: string,
+      onSuccess?: () => void
+    ) => mutation.mutate({ username, password }, { onSuccess }),
     isPending: mutation.isPending,
     error: mutation.error,
     reset: mutation.reset
diff --git a/rsconcept/frontend/src/backend/auth/useLogout.tsx b/rsconcept/frontend/src/backend/auth/useLogout.tsx
index f0f9b252..9bb5e3cd 100644
--- a/rsconcept/frontend/src/backend/auth/useLogout.tsx
+++ b/rsconcept/frontend/src/backend/auth/useLogout.tsx
@@ -3,11 +3,11 @@ import { useMutation, useQueryClient } from '@tanstack/react-query';
 import { authApi } from './api';
 
 export const useLogout = () => {
-  const queryClient = useQueryClient();
+  const client = useQueryClient();
   const mutation = useMutation({
     mutationKey: ['logout'],
     mutationFn: authApi.logout,
-    onSettled: () => queryClient.invalidateQueries({ queryKey: [authApi.baseKey] })
+    onSettled: async () => await client.invalidateQueries({ queryKey: [authApi.baseKey] })
   });
   return { logout: (onSuccess?: () => void) => mutation.mutate(undefined, { onSuccess }) };
 };
diff --git a/rsconcept/frontend/src/backend/auth/useRequestPasswordReset.tsx b/rsconcept/frontend/src/backend/auth/useRequestPasswordReset.tsx
index f31d5118..cd6668a7 100644
--- a/rsconcept/frontend/src/backend/auth/useRequestPasswordReset.tsx
+++ b/rsconcept/frontend/src/backend/auth/useRequestPasswordReset.tsx
@@ -8,7 +8,10 @@ export const useRequestPasswordReset = () => {
     mutationFn: authApi.requestPasswordReset
   });
   return {
-    requestPasswordReset: (data: IRequestPasswordDTO, onSuccess?: () => void) => mutation.mutate(data, { onSuccess }),
+    requestPasswordReset: (
+      data: IRequestPasswordDTO, //
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess }),
     isPending: mutation.isPending,
     error: mutation.error,
     reset: mutation.reset
diff --git a/rsconcept/frontend/src/backend/auth/useResetPassword.tsx b/rsconcept/frontend/src/backend/auth/useResetPassword.tsx
index 683c05c6..17f05316 100644
--- a/rsconcept/frontend/src/backend/auth/useResetPassword.tsx
+++ b/rsconcept/frontend/src/backend/auth/useResetPassword.tsx
@@ -3,20 +3,26 @@ import { useMutation, useQueryClient } from '@tanstack/react-query';
 import { authApi, IPasswordTokenDTO, IResetPasswordDTO } from './api';
 
 export const useResetPassword = () => {
-  const queryClient = useQueryClient();
+  const client = useQueryClient();
   const validateMutation = useMutation({
     mutationKey: ['reset-password'],
     mutationFn: authApi.validatePasswordToken,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: [authApi.baseKey] })
+    onSuccess: async () => await client.invalidateQueries({ queryKey: [authApi.baseKey] })
   });
   const resetMutation = useMutation({
     mutationKey: ['reset-password'],
     mutationFn: authApi.resetPassword,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: [authApi.baseKey] })
+    onSuccess: async () => await client.invalidateQueries({ queryKey: [authApi.baseKey] })
   });
   return {
-    validateToken: (data: IPasswordTokenDTO, onSuccess?: () => void) => validateMutation.mutate(data, { onSuccess }),
-    resetPassword: (data: IResetPasswordDTO, onSuccess?: () => void) => resetMutation.mutate(data, { onSuccess }),
+    validateToken: (
+      data: IPasswordTokenDTO, //
+      onSuccess?: () => void
+    ) => validateMutation.mutate(data, { onSuccess }),
+    resetPassword: (
+      data: IResetPasswordDTO, //
+      onSuccess?: () => void
+    ) => resetMutation.mutate(data, { onSuccess }),
     isPending: resetMutation.isPending,
     error: resetMutation.error,
     reset: resetMutation.reset
diff --git a/rsconcept/frontend/src/backend/apiConfiguration.ts b/rsconcept/frontend/src/backend/axiosInstance.ts
similarity index 100%
rename from rsconcept/frontend/src/backend/apiConfiguration.ts
rename to rsconcept/frontend/src/backend/axiosInstance.ts
diff --git a/rsconcept/frontend/src/backend/cctext.ts b/rsconcept/frontend/src/backend/cctext.ts
deleted file mode 100644
index 46b064ca..00000000
--- a/rsconcept/frontend/src/backend/cctext.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-/**
- * Endpoints: cctext.
- */
-
-import { ILexemeData, ITextRequest, ITextResult, IWordFormPlain } from '@/models/language';
-
-import { AxiosPost, FrontExchange } from './apiTransport';
-
-export function postInflectText(request: FrontExchange<IWordFormPlain, ITextResult>) {
-  AxiosPost({
-    endpoint: `/api/cctext/inflect`,
-    request: request
-  });
-}
-
-export function postParseText(request: FrontExchange<ITextRequest, ITextResult>) {
-  AxiosPost({
-    endpoint: `/api/cctext/parse`,
-    request: request
-  });
-}
-
-export function postGenerateLexeme(request: FrontExchange<ITextRequest, ILexemeData>) {
-  AxiosPost({
-    endpoint: `/api/cctext/generate-lexeme`,
-    request: request
-  });
-}
diff --git a/rsconcept/frontend/src/backend/cctext/api.ts b/rsconcept/frontend/src/backend/cctext/api.ts
new file mode 100644
index 00000000..b968ed91
--- /dev/null
+++ b/rsconcept/frontend/src/backend/cctext/api.ts
@@ -0,0 +1,26 @@
+import { axiosInstance } from '@/backend/axiosInstance';
+import { ILexemeData, IWordFormPlain } from '@/models/language';
+
+/**
+ * Represents API result for text output.
+ */
+export interface ITextResult {
+  result: string;
+}
+
+export const cctextApi = {
+  baseKey: 'cctext',
+
+  inflectText: (data: IWordFormPlain) =>
+    axiosInstance //
+      .post<ITextResult>('/api/cctext/inflect', data)
+      .then(response => response.data),
+  parseText: (data: { text: string }) =>
+    axiosInstance //
+      .post<ITextResult>('/api/cctext/parse', data)
+      .then(response => response.data),
+  generateLexeme: (data: { text: string }) =>
+    axiosInstance //
+      .post<ILexemeData>('/api/cctext/generate-lexeme', data)
+      .then(response => response.data)
+};
diff --git a/rsconcept/frontend/src/backend/cctext/useGenerateLexeme.tsx b/rsconcept/frontend/src/backend/cctext/useGenerateLexeme.tsx
new file mode 100644
index 00000000..e04f01f9
--- /dev/null
+++ b/rsconcept/frontend/src/backend/cctext/useGenerateLexeme.tsx
@@ -0,0 +1,19 @@
+import { useMutation } from '@tanstack/react-query';
+
+import { ILexemeData } from '@/models/language';
+
+import { DataCallback } from '../apiTransport';
+import { cctextApi } from './api';
+
+export const useGenerateLexeme = () => {
+  const mutation = useMutation({
+    mutationKey: [cctextApi.baseKey, 'generate-lexeme'],
+    mutationFn: cctextApi.generateLexeme
+  });
+  return {
+    generateLexeme: (
+      data: { text: string }, //
+      onSuccess?: DataCallback<ILexemeData>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/cctext/useInflectText.tsx b/rsconcept/frontend/src/backend/cctext/useInflectText.tsx
new file mode 100644
index 00000000..73a4dfb6
--- /dev/null
+++ b/rsconcept/frontend/src/backend/cctext/useInflectText.tsx
@@ -0,0 +1,19 @@
+import { useMutation } from '@tanstack/react-query';
+
+import { IWordFormPlain } from '@/models/language';
+
+import { DataCallback } from '../apiTransport';
+import { cctextApi, ITextResult } from './api';
+
+export const useInflectText = () => {
+  const mutation = useMutation({
+    mutationKey: [cctextApi.baseKey, 'inflect-text'],
+    mutationFn: cctextApi.inflectText
+  });
+  return {
+    inflectText: (
+      data: IWordFormPlain, //
+      onSuccess?: DataCallback<ITextResult>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/cctext/useIsProcessingCctext.tsx b/rsconcept/frontend/src/backend/cctext/useIsProcessingCctext.tsx
new file mode 100644
index 00000000..401a032e
--- /dev/null
+++ b/rsconcept/frontend/src/backend/cctext/useIsProcessingCctext.tsx
@@ -0,0 +1,8 @@
+import { useIsMutating } from '@tanstack/react-query';
+
+import { cctextApi } from './api';
+
+export const useIsProcessingCctext = () => {
+  const countMutations = useIsMutating({ mutationKey: [cctextApi.baseKey] });
+  return countMutations !== 0;
+};
diff --git a/rsconcept/frontend/src/backend/cctext/useParseText.tsx b/rsconcept/frontend/src/backend/cctext/useParseText.tsx
new file mode 100644
index 00000000..463878a2
--- /dev/null
+++ b/rsconcept/frontend/src/backend/cctext/useParseText.tsx
@@ -0,0 +1,17 @@
+import { useMutation } from '@tanstack/react-query';
+
+import { DataCallback } from '../apiTransport';
+import { cctextApi, ITextResult } from './api';
+
+export const useParseText = () => {
+  const mutation = useMutation({
+    mutationKey: [cctextApi.baseKey, 'parse-text'],
+    mutationFn: cctextApi.parseText
+  });
+  return {
+    parseText: (
+      data: { text: string }, //
+      onSuccess?: DataCallback<ITextResult>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/configuration.ts b/rsconcept/frontend/src/backend/configuration.ts
new file mode 100644
index 00000000..fdb5d8a9
--- /dev/null
+++ b/rsconcept/frontend/src/backend/configuration.ts
@@ -0,0 +1,9 @@
+/** Timing constants for API requests. */
+export const DELAYS = {
+  garbageCollection: 1 * 60 * 60 * 1000,
+  staleDefault: 5 * 60 * 1000,
+
+  staleShort: 5 * 60 * 1000,
+  staleMedium: 1 * 60 * 60 * 1000,
+  staleLong: 24 * 60 * 60 * 1000
+};
diff --git a/rsconcept/frontend/src/backend/library.ts b/rsconcept/frontend/src/backend/library.ts
deleted file mode 100644
index a8990727..00000000
--- a/rsconcept/frontend/src/backend/library.ts
+++ /dev/null
@@ -1,117 +0,0 @@
-/**
- * Endpoints: library.
- */
-
-import {
-  ILibraryCreateData,
-  ILibraryItem,
-  ILibraryUpdateData,
-  IRenameLocationData,
-  ITargetAccessPolicy,
-  ITargetLocation,
-  IVersionCreateData
-} from '@/models/library';
-import { IRSFormCloneData, IRSFormData, IVersionCreatedResponse } from '@/models/rsform';
-import { ITargetUser, ITargetUsers } from '@/models/user';
-
-import {
-  AxiosDelete,
-  AxiosGet,
-  AxiosPatch,
-  AxiosPost,
-  FrontAction,
-  FrontExchange,
-  FrontPull,
-  FrontPush
-} from './apiTransport';
-
-export function getLibrary(request: FrontPull<ILibraryItem[]>) {
-  AxiosGet({
-    endpoint: '/api/library/active',
-    request: request
-  });
-}
-
-export function getAdminLibrary(request: FrontPull<ILibraryItem[]>) {
-  AxiosGet({
-    endpoint: '/api/library/all',
-    request: request
-  });
-}
-
-export function getTemplates(request: FrontPull<ILibraryItem[]>) {
-  AxiosGet({
-    endpoint: '/api/library/templates',
-    request: request
-  });
-}
-
-export function postCreateLibraryItem(request: FrontExchange<ILibraryCreateData, ILibraryItem>) {
-  AxiosPost({
-    endpoint: '/api/library',
-    request: request
-  });
-}
-
-export function postCloneLibraryItem(target: string, request: FrontExchange<IRSFormCloneData, IRSFormData>) {
-  AxiosPost({
-    endpoint: `/api/library/${target}/clone`,
-    request: request
-  });
-}
-
-export function patchLibraryItem(target: string, request: FrontExchange<ILibraryUpdateData, ILibraryItem>) {
-  AxiosPatch({
-    endpoint: `/api/library/${target}`,
-    request: request
-  });
-}
-
-export function deleteLibraryItem(target: string, request: FrontAction) {
-  AxiosDelete({
-    endpoint: `/api/library/${target}`,
-    request: request
-  });
-}
-
-export function patchSetOwner(target: string, request: FrontPush<ITargetUser>) {
-  AxiosPatch({
-    endpoint: `/api/library/${target}/set-owner`,
-    request: request
-  });
-}
-
-export function patchSetAccessPolicy(target: string, request: FrontPush<ITargetAccessPolicy>) {
-  AxiosPatch({
-    endpoint: `/api/library/${target}/set-access-policy`,
-    request: request
-  });
-}
-
-export function patchSetLocation(target: string, request: FrontPush<ITargetLocation>) {
-  AxiosPatch({
-    endpoint: `/api/library/${target}/set-location`,
-    request: request
-  });
-}
-
-export function patchRenameLocation(request: FrontPush<IRenameLocationData>) {
-  AxiosPatch({
-    endpoint: `/api/library/rename-location`,
-    request: request
-  });
-}
-
-export function patchSetEditors(target: string, request: FrontPush<ITargetUsers>) {
-  AxiosPatch({
-    endpoint: `/api/library/${target}/set-editors`,
-    request: request
-  });
-}
-
-export function postCreateVersion(target: string, request: FrontExchange<IVersionCreateData, IVersionCreatedResponse>) {
-  AxiosPost({
-    endpoint: `/api/library/${target}/create-version`,
-    request: request
-  });
-}
diff --git a/rsconcept/frontend/src/backend/library/api.ts b/rsconcept/frontend/src/backend/library/api.ts
new file mode 100644
index 00000000..1afc069c
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/api.ts
@@ -0,0 +1,137 @@
+import { queryOptions } from '@tanstack/react-query';
+
+import { axiosInstance } from '@/backend/axiosInstance';
+import { DELAYS } from '@/backend/configuration';
+import { AccessPolicy, ILibraryItem, IVersionData, LibraryItemID, VersionID } from '@/models/library';
+import { ConstituentaID, IRSFormData } from '@/models/rsform';
+import { UserID } from '@/models/user';
+
+/**
+ * Represents update data for renaming Location.
+ */
+export interface IRenameLocationDTO {
+  target: string;
+  new_location: string;
+}
+
+/**
+ * Represents data, used for cloning {@link IRSForm}.
+ */
+export interface IRSFormCloneDTO extends Omit<ILibraryItem, 'time_create' | 'time_update' | 'owner'> {
+  items?: ConstituentaID[];
+}
+
+/**
+ * Represents data, used for creating {@link IRSForm}.
+ */
+export interface ILibraryCreateDTO extends Omit<ILibraryItem, 'time_create' | 'time_update' | 'id' | 'owner'> {
+  file?: File;
+  fileName?: string;
+}
+
+/**
+ * Represents update data for editing {@link ILibraryItem}.
+ */
+export interface ILibraryUpdateDTO
+  extends Omit<ILibraryItem, 'time_create' | 'time_update' | 'access_policy' | 'location' | 'owner'> {}
+
+/**
+ * Create version metadata in persistent storage.
+ */
+export interface IVersionCreateDTO {
+  version: string;
+  description: string;
+  items?: ConstituentaID[];
+}
+
+/**
+ * Represents data response when creating {@link IVersionInfo}.
+ */
+export interface IVersionCreatedResponse {
+  version: number;
+  schema: IRSFormData;
+}
+
+export const libraryApi = {
+  baseKey: 'library',
+  libraryListKey: ['library', 'list'],
+
+  getLibraryQueryOptions: ({ isAdmin }: { isAdmin: boolean }) =>
+    queryOptions({
+      queryKey: libraryApi.libraryListKey,
+      staleTime: DELAYS.staleMedium,
+      queryFn: meta =>
+        axiosInstance
+          .get<ILibraryItem[]>(isAdmin ? '/api/library/all' : '/api/library/active', {
+            signal: meta.signal
+          })
+          .then(response => response.data)
+    }),
+  getTemplatesQueryOptions: () =>
+    queryOptions({
+      queryKey: [libraryApi.baseKey, 'templates'],
+      staleTime: DELAYS.staleMedium,
+      queryFn: meta =>
+        axiosInstance
+          .get<ILibraryItem[]>('/api/library/templates', {
+            signal: meta.signal
+          })
+          .then(response => response.data)
+    }),
+
+  createItem: (data: ILibraryCreateDTO) =>
+    data.file
+      ? axiosInstance
+          .post<ILibraryItem>('/api/rsforms/create-detailed', data, {
+            headers: {
+              'Content-Type': 'multipart/form-data'
+            }
+          })
+          .then(response => response.data)
+      : axiosInstance //
+          .post<ILibraryItem>('/api/library', data)
+          .then(response => response.data),
+
+  updateItem: (data: ILibraryUpdateDTO) =>
+    axiosInstance //
+      .patch<ILibraryItem>(`/api/library/${data.id}`, data)
+      .then(response => response.data),
+  setOwner: (data: { itemID: LibraryItemID; owner: UserID }) =>
+    axiosInstance //
+      .patch(`/api/library/${data.itemID}/set-owner`, { user: data.owner }),
+  setLocation: (data: { itemID: LibraryItemID; location: string }) =>
+    axiosInstance //
+      .patch(`/api/library/${data.itemID}/set-location`, { location: data.location }),
+  setAccessPolicy: (data: { itemID: LibraryItemID; policy: AccessPolicy }) =>
+    axiosInstance //
+      .patch(`/api/library/${data.itemID}/set-access-policy`, { access_policy: data.policy }),
+  setEditors: (data: { itemID: LibraryItemID; editors: UserID[] }) =>
+    axiosInstance //
+      .patch(`/api/library/${data.itemID}/set-editors`, { users: data.editors }),
+
+  deleteItem: (target: LibraryItemID) =>
+    axiosInstance //
+      .delete(`/api/library/${target}`),
+  cloneItem: (data: IRSFormCloneDTO) =>
+    axiosInstance //
+      .post<IRSFormData>(`/api/library/${data.id}/clone`, data)
+      .then(response => response.data),
+  renameLocation: (data: IRenameLocationDTO) =>
+    axiosInstance //
+      .patch('/api/library/rename-location', data),
+
+  versionCreate: (data: { itemID: LibraryItemID; data: IVersionData }) =>
+    axiosInstance //
+      .post<IVersionCreatedResponse>(`/api/library/${data.itemID}/versions`, data.data)
+      .then(response => response.data),
+  versionRestore: (data: { itemID: LibraryItemID; versionID: VersionID }) =>
+    axiosInstance //
+      .patch<IRSFormData>(`/api/versions/${data.versionID}/restore`)
+      .then(response => response.data),
+  versionUpdate: (data: { itemID: LibraryItemID; versionID: VersionID; data: IVersionData }) =>
+    axiosInstance //
+      .patch(`/api/versions/${data.versionID}`, data.data),
+  versionDelete: (data: { itemID: LibraryItemID; versionID: VersionID }) =>
+    axiosInstance //
+      .delete(`/api/versions/${data.versionID}`)
+};
diff --git a/rsconcept/frontend/src/backend/library/useApplyLibraryFilter.tsx b/rsconcept/frontend/src/backend/library/useApplyLibraryFilter.tsx
new file mode 100644
index 00000000..4281e2ef
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useApplyLibraryFilter.tsx
@@ -0,0 +1,47 @@
+import { useAuth } from '@/backend/auth/useAuth';
+import { matchLibraryItem, matchLibraryItemLocation } from '@/models/libraryAPI';
+import { ILibraryFilter } from '@/models/miscellaneous';
+
+import { useLibrary } from './useLibrary';
+
+export function useApplyLibraryFilter(filter: ILibraryFilter) {
+  const { items } = useLibrary();
+  const { user } = useAuth();
+
+  let result = items;
+  if (!filter.folderMode && filter.head) {
+    result = result.filter(item => item.location.startsWith(filter.head!));
+  }
+  if (filter.folderMode && filter.location) {
+    if (filter.subfolders) {
+      result = result.filter(
+        item => item.location == filter.location || item.location.startsWith(filter.location! + '/')
+      );
+    } else {
+      result = result.filter(item => item.location == filter.location);
+    }
+  }
+  if (filter.type) {
+    result = result.filter(item => item.item_type === filter.type);
+  }
+  if (filter.isVisible !== undefined) {
+    result = result.filter(item => filter.isVisible === item.visible);
+  }
+  if (filter.isOwned !== undefined) {
+    result = result.filter(item => filter.isOwned === (item.owner === user?.id));
+  }
+  if (filter.isEditor !== undefined) {
+    result = result.filter(item => filter.isEditor == user?.editor.includes(item.id));
+  }
+  if (filter.filterUser !== undefined) {
+    result = result.filter(item => filter.filterUser === item.owner);
+  }
+  if (!filter.folderMode && filter.path) {
+    result = result.filter(item => matchLibraryItemLocation(item, filter.path!));
+  }
+  if (filter.query) {
+    result = result.filter(item => matchLibraryItem(item, filter.query!));
+  }
+
+  return { filtered: result };
+}
diff --git a/rsconcept/frontend/src/backend/library/useCloneItem.tsx b/rsconcept/frontend/src/backend/library/useCloneItem.tsx
new file mode 100644
index 00000000..0609a435
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useCloneItem.tsx
@@ -0,0 +1,21 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { IRSFormData } from '@/models/rsform';
+
+import { IRSFormCloneDTO, libraryApi } from './api';
+
+export const useCloneItem = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'clone-item'],
+    mutationFn: libraryApi.cloneItem,
+    onSuccess: async () => await client.invalidateQueries({ queryKey: [libraryApi.baseKey] })
+  });
+  return {
+    cloneItem: (
+      data: IRSFormCloneDTO, //
+      onSuccess?: DataCallback<IRSFormData>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useCreateItem.tsx b/rsconcept/frontend/src/backend/library/useCreateItem.tsx
new file mode 100644
index 00000000..a61c2a88
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useCreateItem.tsx
@@ -0,0 +1,24 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { ILibraryItem } from '@/models/library';
+
+import { ILibraryCreateDTO, libraryApi } from './api';
+
+export const useCreateItem = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'create-item'],
+    mutationFn: libraryApi.createItem,
+    onSuccess: () => client.invalidateQueries({ queryKey: [libraryApi.baseKey] })
+  });
+  return {
+    createItem: (
+      data: ILibraryCreateDTO, //
+      onSuccess?: DataCallback<ILibraryItem>
+    ) => mutation.mutate(data, { onSuccess }),
+    isPending: mutation.isPending,
+    error: mutation.error,
+    reset: mutation.reset
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useDeleteItem.tsx b/rsconcept/frontend/src/backend/library/useDeleteItem.tsx
new file mode 100644
index 00000000..b44e6f6b
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useDeleteItem.tsx
@@ -0,0 +1,26 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { ILibraryItem, LibraryItemID } from '@/models/library';
+
+import { libraryApi } from './api';
+
+export const useDeleteItem = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'delete-item'],
+    mutationFn: libraryApi.deleteItem,
+    onSuccess: async (_, variables) => {
+      await client.cancelQueries({ queryKey: [libraryApi.libraryListKey] });
+      client.setQueryData(libraryApi.libraryListKey, (prev: ILibraryItem[] | undefined) =>
+        prev?.filter(item => item.id !== variables)
+      );
+    }
+  });
+  return {
+    deleteItem: (
+      target: LibraryItemID, //
+      onSuccess?: () => void
+    ) => mutation.mutate(target, { onSuccess }),
+    isPending: mutation.isPending
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useFolders.tsx b/rsconcept/frontend/src/backend/library/useFolders.tsx
new file mode 100644
index 00000000..d793a111
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useFolders.tsx
@@ -0,0 +1,17 @@
+import { FolderTree } from '@/models/FolderTree';
+import { LocationHead } from '@/models/library';
+
+import { useLibrary } from './useLibrary';
+
+export function useFolders() {
+  const { items } = useLibrary();
+
+  const result = new FolderTree();
+  result.addPath(LocationHead.USER, 0);
+  result.addPath(LocationHead.COMMON, 0);
+  result.addPath(LocationHead.LIBRARY, 0);
+  result.addPath(LocationHead.PROJECTS, 0);
+  items.forEach(item => result.addPath(item.location));
+
+  return { folders: result };
+}
diff --git a/rsconcept/frontend/src/backend/library/useIsProcessingLibrary.tsx b/rsconcept/frontend/src/backend/library/useIsProcessingLibrary.tsx
new file mode 100644
index 00000000..c278c6ea
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useIsProcessingLibrary.tsx
@@ -0,0 +1,8 @@
+import { useIsMutating } from '@tanstack/react-query';
+
+import { libraryApi } from './api';
+
+export const useIsProcessingLibrary = () => {
+  const countMutations = useIsMutating({ mutationKey: [libraryApi.baseKey] });
+  return countMutations !== 0;
+};
diff --git a/rsconcept/frontend/src/backend/library/useLibrary.tsx b/rsconcept/frontend/src/backend/library/useLibrary.tsx
new file mode 100644
index 00000000..6fb112e7
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useLibrary.tsx
@@ -0,0 +1,21 @@
+import { useQuery, useSuspenseQuery } from '@tanstack/react-query';
+
+import { useAuthSuspense } from '@/backend/auth/useAuth';
+import { libraryApi } from './api';
+
+export function useLibrarySuspense() {
+  const { user } = useAuthSuspense();
+  const { data: items } = useSuspenseQuery({
+    ...libraryApi.getLibraryQueryOptions({ isAdmin: user?.is_staff ?? false })
+  });
+  return { items };
+}
+
+export function useLibrary() {
+  // NOTE: Using suspense here to avoid duplicated library data requests
+  const { user } = useAuthSuspense();
+  const { data: items, isLoading } = useQuery({
+    ...libraryApi.getLibraryQueryOptions({ isAdmin: user?.is_staff ?? false })
+  });
+  return { items: items ?? [], isLoading };
+}
diff --git a/rsconcept/frontend/src/backend/library/useRenameLocation.tsx b/rsconcept/frontend/src/backend/library/useRenameLocation.tsx
new file mode 100644
index 00000000..0767c7e8
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useRenameLocation.tsx
@@ -0,0 +1,18 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { IRenameLocationDTO, libraryApi } from './api';
+
+export const useRenameLocation = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'rename-location'],
+    mutationFn: libraryApi.renameLocation,
+    onSuccess: () => client.invalidateQueries({ queryKey: [libraryApi.baseKey] })
+  });
+  return {
+    renameLocation: (
+      data: IRenameLocationDTO, //
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useSetAccessPolicy.tsx b/rsconcept/frontend/src/backend/library/useSetAccessPolicy.tsx
new file mode 100644
index 00000000..6d26c1a0
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useSetAccessPolicy.tsx
@@ -0,0 +1,41 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { rsformsApi } from '@/backend/rsform/api';
+import { AccessPolicy, ILibraryItem, LibraryItemID, LibraryItemType } from '@/models/library';
+
+import { libraryApi } from './api';
+
+export const useSetAccessPolicy = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'set-location'],
+    mutationFn: libraryApi.setAccessPolicy,
+    onSuccess: (_, variables) => {
+      client.setQueryData(libraryApi.libraryListKey, (prev: ILibraryItem[] | undefined) =>
+        prev?.map(item => (item.id === variables.itemID ? { ...item, access_policy: variables.policy } : item))
+      );
+      client.setQueryData(rsformsApi.getRSFormQueryOptions({ itemID: variables.itemID }).queryKey, prev => {
+        if (!prev) {
+          return undefined;
+        }
+        if (prev.item_type === LibraryItemType.OSS) {
+          client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] }).catch(console.error);
+        }
+        return {
+          ...prev,
+          access_policy: variables.policy
+        };
+      });
+    }
+  });
+
+  return {
+    setAccessPolicy: (
+      data: {
+        itemID: LibraryItemID; //
+        policy: AccessPolicy;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useSetEditors.tsx b/rsconcept/frontend/src/backend/library/useSetEditors.tsx
new file mode 100644
index 00000000..89b066f1
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useSetEditors.tsx
@@ -0,0 +1,39 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { rsformsApi } from '@/backend/rsform/api';
+import { ILibraryItem, LibraryItemID } from '@/models/library';
+import { UserID } from '@/models/user';
+
+import { libraryApi } from './api';
+
+export const useSetEditors = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'set-location'],
+    mutationFn: libraryApi.setEditors,
+    onSuccess: (_, variables) => {
+      client.setQueryData(libraryApi.libraryListKey, (prev: ILibraryItem[] | undefined) =>
+        prev?.map(item => (item.id === variables.itemID ? { ...item, editors: variables.editors } : item))
+      );
+      client.setQueryData(rsformsApi.getRSFormQueryOptions({ itemID: variables.itemID }).queryKey, prev => {
+        if (!prev) {
+          return undefined;
+        }
+        return {
+          ...prev,
+          editors: variables.editors
+        };
+      });
+    }
+  });
+
+  return {
+    setEditors: (
+      data: {
+        itemID: LibraryItemID; //
+        editors: UserID[];
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useSetLocation.tsx b/rsconcept/frontend/src/backend/library/useSetLocation.tsx
new file mode 100644
index 00000000..ae143d49
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useSetLocation.tsx
@@ -0,0 +1,41 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { rsformsApi } from '@/backend/rsform/api';
+import { ILibraryItem, LibraryItemID, LibraryItemType } from '@/models/library';
+
+import { libraryApi } from './api';
+
+export const useSetLocation = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'set-location'],
+    mutationFn: libraryApi.setLocation,
+    onSuccess: (_, variables) => {
+      client.setQueryData(libraryApi.libraryListKey, (prev: ILibraryItem[] | undefined) =>
+        prev?.map(item => (item.id === variables.itemID ? { ...item, location: variables.location } : item))
+      );
+      client.setQueryData(rsformsApi.getRSFormQueryOptions({ itemID: variables.itemID }).queryKey, prev => {
+        if (!prev) {
+          return undefined;
+        }
+        if (prev.item_type === LibraryItemType.OSS) {
+          client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] }).catch(console.error);
+        }
+        return {
+          ...prev,
+          location: variables.location
+        };
+      });
+    }
+  });
+
+  return {
+    setLocation: (
+      data: {
+        itemID: LibraryItemID; //
+        location: string;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useSetOwner.tsx b/rsconcept/frontend/src/backend/library/useSetOwner.tsx
new file mode 100644
index 00000000..96dbcc89
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useSetOwner.tsx
@@ -0,0 +1,42 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { rsformsApi } from '@/backend/rsform/api';
+import { ILibraryItem, LibraryItemID, LibraryItemType } from '@/models/library';
+import { UserID } from '@/models/user';
+
+import { libraryApi } from './api';
+
+export const useSetOwner = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'set-owner'],
+    mutationFn: libraryApi.setOwner,
+    onSuccess: (_, variables) => {
+      client.setQueryData(libraryApi.libraryListKey, (prev: ILibraryItem[] | undefined) =>
+        prev?.map(item => (item.id === variables.itemID ? { ...item, owner: variables.owner } : item))
+      );
+      client.setQueryData(rsformsApi.getRSFormQueryOptions({ itemID: variables.itemID }).queryKey, prev => {
+        if (!prev) {
+          return undefined;
+        }
+        if (prev.item_type === LibraryItemType.OSS) {
+          client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] }).catch(console.error);
+        }
+        return {
+          ...prev,
+          owner: variables.owner
+        };
+      });
+    }
+  });
+
+  return {
+    setOwner: (
+      data: {
+        itemID: LibraryItemID; //
+        owner: UserID;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useTemplates.tsx b/rsconcept/frontend/src/backend/library/useTemplates.tsx
new file mode 100644
index 00000000..3af2c235
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useTemplates.tsx
@@ -0,0 +1,17 @@
+import { useQuery, useSuspenseQuery } from '@tanstack/react-query';
+
+import { libraryApi } from './api';
+
+export function useTemplatesSuspense() {
+  const { data: templates } = useSuspenseQuery({
+    ...libraryApi.getTemplatesQueryOptions()
+  });
+  return { templates };
+}
+
+export function useTemplates() {
+  const { data: templates } = useQuery({
+    ...libraryApi.getTemplatesQueryOptions()
+  });
+  return { templates: templates ?? [] };
+}
diff --git a/rsconcept/frontend/src/backend/library/useUpdateItem.tsx b/rsconcept/frontend/src/backend/library/useUpdateItem.tsx
new file mode 100644
index 00000000..53e0d80b
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useUpdateItem.tsx
@@ -0,0 +1,34 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { rsformsApi } from '@/backend/rsform/api';
+import { ILibraryItem } from '@/models/library';
+
+import { ILibraryUpdateDTO, libraryApi } from './api';
+
+export const useUpdateItem = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'update-item'],
+    mutationFn: libraryApi.updateItem,
+    onSuccess: (data: ILibraryItem) => {
+      client
+        .cancelQueries({ queryKey: [libraryApi.libraryListKey] })
+        .then(async () => {
+          client.setQueryData(libraryApi.libraryListKey, (prev: ILibraryItem[] | undefined) =>
+            prev?.map(item => (item.id === data.id ? data : item))
+          );
+          await client.invalidateQueries({
+            queryKey: [rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey]
+          });
+        })
+        .catch(console.error);
+    }
+  });
+  return {
+    updateItem: (
+      data: ILibraryUpdateDTO, //
+      onSuccess?: DataCallback<ILibraryItem>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useUpdateTimestamp.tsx b/rsconcept/frontend/src/backend/library/useUpdateTimestamp.tsx
new file mode 100644
index 00000000..1e82548c
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useUpdateTimestamp.tsx
@@ -0,0 +1,17 @@
+import { useQueryClient } from '@tanstack/react-query';
+
+import { ILibraryItem, LibraryItemID } from '@/models/library';
+
+import { libraryApi } from './api';
+
+export function useUpdateTimestamp() {
+  const client = useQueryClient();
+  return {
+    updateTimestamp: (target: LibraryItemID) =>
+      client.setQueryData(
+        libraryApi.libraryListKey, //
+        (prev: ILibraryItem[] | undefined) =>
+          prev?.map(item => (item.id === target ? { ...item, time_update: Date() } : item))
+      )
+  };
+}
diff --git a/rsconcept/frontend/src/backend/library/useVersionCreate.tsx b/rsconcept/frontend/src/backend/library/useVersionCreate.tsx
new file mode 100644
index 00000000..94bfee8a
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useVersionCreate.tsx
@@ -0,0 +1,30 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { rsformsApi } from '@/backend/rsform/api';
+import { IVersionData, LibraryItemID } from '@/models/library';
+
+import { libraryApi } from './api';
+
+export const useVersionCreate = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'create-version'],
+    mutationFn: libraryApi.versionCreate,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.schema.id }).queryKey], data.schema);
+      updateTimestamp(data.schema.id);
+    }
+  });
+  return {
+    versionCreate: (
+      data: {
+        itemID: LibraryItemID; //
+        data: IVersionData;
+      },
+      onSuccess?: DataCallback<IVersionData>
+    ) => mutation.mutate(data, { onSuccess: () => onSuccess?.(data.data) })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useVersionDelete.tsx b/rsconcept/frontend/src/backend/library/useVersionDelete.tsx
new file mode 100644
index 00000000..e13de4f0
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useVersionDelete.tsx
@@ -0,0 +1,33 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { rsformsApi } from '@/backend/rsform/api';
+import { LibraryItemID, VersionID } from '@/models/library';
+import { IRSFormData } from '@/models/rsform';
+
+import { libraryApi } from './api';
+
+export const useVersionDelete = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'delete-version'],
+    mutationFn: libraryApi.versionDelete,
+    onSuccess: (_, variables) => {
+      client.setQueryData(
+        [rsformsApi.getRSFormQueryOptions({ itemID: variables.itemID }).queryKey],
+        (prev: IRSFormData) => ({
+          ...prev,
+          versions: prev.versions.filter(version => version.id !== variables.versionID)
+        })
+      );
+    }
+  });
+  return {
+    versionDelete: (
+      data: {
+        itemID: LibraryItemID; //
+        versionID: VersionID;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useVersionRestore.tsx b/rsconcept/frontend/src/backend/library/useVersionRestore.tsx
new file mode 100644
index 00000000..e5cf8aeb
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useVersionRestore.tsx
@@ -0,0 +1,29 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { rsformsApi } from '@/backend/rsform/api';
+import { LibraryItemID, VersionID } from '@/models/library';
+
+import { libraryApi } from './api';
+
+export const useVersionRestore = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'restore-version'],
+    mutationFn: libraryApi.versionRestore,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey], data);
+      updateTimestamp(data.id);
+    }
+  });
+  return {
+    versionRestore: (
+      data: {
+        itemID: LibraryItemID; //
+        versionID: VersionID;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/library/useVersionUpdate.tsx b/rsconcept/frontend/src/backend/library/useVersionUpdate.tsx
new file mode 100644
index 00000000..c6d8d8ec
--- /dev/null
+++ b/rsconcept/frontend/src/backend/library/useVersionUpdate.tsx
@@ -0,0 +1,38 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { rsformsApi } from '@/backend/rsform/api';
+import { IVersionData, LibraryItemID, VersionID } from '@/models/library';
+import { IRSFormData } from '@/models/rsform';
+
+import { libraryApi } from './api';
+
+export const useVersionUpdate = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [libraryApi.baseKey, 'update-version'],
+    mutationFn: libraryApi.versionUpdate,
+    onSuccess: (_, variables) => {
+      client.setQueryData(
+        [rsformsApi.getRSFormQueryOptions({ itemID: variables.itemID }).queryKey],
+        (prev: IRSFormData) => ({
+          ...prev,
+          versions: prev.versions.map(version =>
+            version.id === variables.versionID
+              ? { ...version, description: variables.data.description, version: variables.data.version }
+              : version
+          )
+        })
+      );
+    }
+  });
+  return {
+    versionUpdate: (
+      data: {
+        itemID: LibraryItemID; //
+        versionID: VersionID;
+        data: IVersionData;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss.ts b/rsconcept/frontend/src/backend/oss.ts
deleted file mode 100644
index a9f63858..00000000
--- a/rsconcept/frontend/src/backend/oss.ts
+++ /dev/null
@@ -1,92 +0,0 @@
-/**
- * Endpoints: oss.
- */
-
-import {
-  ICstRelocateData,
-  IInputCreatedResponse,
-  IOperationCreateData,
-  IOperationCreatedResponse,
-  IOperationDeleteData,
-  IOperationSchemaData,
-  IOperationSetInputData,
-  IOperationUpdateData,
-  IPositionsData,
-  ITargetOperation
-} from '@/models/oss';
-import { IConstituentaReference, ITargetCst } from '@/models/rsform';
-
-import { AxiosGet, AxiosPatch, AxiosPost, FrontExchange, FrontPull, FrontPush } from './apiTransport';
-
-export function getOssDetails(target: string, request: FrontPull<IOperationSchemaData>) {
-  AxiosGet({
-    endpoint: `/api/oss/${target}/details`,
-    request: request
-  });
-}
-
-export function patchUpdatePositions(oss: string, request: FrontPush<IPositionsData>) {
-  AxiosPatch({
-    endpoint: `/api/oss/${oss}/update-positions`,
-    request: request
-  });
-}
-
-export function postCreateOperation(
-  oss: string,
-  request: FrontExchange<IOperationCreateData, IOperationCreatedResponse>
-) {
-  AxiosPost({
-    endpoint: `/api/oss/${oss}/create-operation`,
-    request: request
-  });
-}
-
-export function patchDeleteOperation(oss: string, request: FrontExchange<IOperationDeleteData, IOperationSchemaData>) {
-  AxiosPatch({
-    endpoint: `/api/oss/${oss}/delete-operation`,
-    request: request
-  });
-}
-
-export function patchCreateInput(oss: string, request: FrontExchange<ITargetOperation, IInputCreatedResponse>) {
-  AxiosPatch({
-    endpoint: `/api/oss/${oss}/create-input`,
-    request: request
-  });
-}
-
-export function patchSetInput(oss: string, request: FrontExchange<IOperationSetInputData, IOperationSchemaData>) {
-  AxiosPatch({
-    endpoint: `/api/oss/${oss}/set-input`,
-    request: request
-  });
-}
-
-export function patchUpdateOperation(oss: string, request: FrontExchange<IOperationUpdateData, IOperationSchemaData>) {
-  AxiosPatch({
-    endpoint: `/api/oss/${oss}/update-operation`,
-    request: request
-  });
-}
-
-export function postExecuteOperation(oss: string, request: FrontExchange<ITargetOperation, IOperationSchemaData>) {
-  AxiosPost({
-    endpoint: `/api/oss/${oss}/execute-operation`,
-    request: request
-  });
-}
-
-export function postRelocateConstituents(request: FrontPush<ICstRelocateData>) {
-  AxiosPost({
-    endpoint: `/api/oss/relocate-constituents`,
-    request: request
-  });
-}
-
-export function postFindPredecessor(request: FrontExchange<ITargetCst, IConstituentaReference>) {
-  AxiosPost({
-    endpoint: `/api/oss/get-predecessor`,
-    request: request
-  });
-}
diff --git a/rsconcept/frontend/src/backend/oss/api.ts b/rsconcept/frontend/src/backend/oss/api.ts
new file mode 100644
index 00000000..4a4d4e8a
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/api.ts
@@ -0,0 +1,148 @@
+import { queryOptions } from '@tanstack/react-query';
+
+import { axiosInstance } from '@/backend/axiosInstance';
+import { DELAYS } from '@/backend/configuration';
+import { ILibraryItem, LibraryItemID } from '@/models/library';
+import {
+  ICstSubstitute,
+  IOperationData,
+  IOperationPosition,
+  IOperationSchemaData,
+  OperationID,
+  OperationType
+} from '@/models/oss';
+import { ConstituentaID, IConstituentaReference, ITargetCst } from '@/models/rsform';
+
+/**
+ * Represents {@link IOperation} data, used in creation process.
+ */
+export interface IOperationCreateDTO {
+  positions: IOperationPosition[];
+  item_data: {
+    alias: string;
+    operation_type: OperationType;
+    title: string;
+    comment: string;
+    position_x: number;
+    position_y: number;
+    result: LibraryItemID | null;
+  };
+  arguments: OperationID[] | undefined;
+  create_schema: boolean;
+}
+
+/**
+ * Represents data response when creating {@link IOperation}.
+ */
+export interface IOperationCreatedResponse {
+  new_operation: IOperationData;
+  oss: IOperationSchemaData;
+}
+
+/**
+ * Represents target {@link IOperation}.
+ */
+export interface ITargetOperation {
+  positions: IOperationPosition[];
+  target: OperationID;
+}
+
+/**
+ * Represents {@link IOperation} data, used in destruction process.
+ */
+export interface IOperationDeleteDTO extends ITargetOperation {
+  keep_constituents: boolean;
+  delete_schema: boolean;
+}
+
+/**
+ * Represents data response when creating {@link IRSForm} for Input {@link IOperation}.
+ */
+export interface IInputCreatedResponse {
+  new_schema: ILibraryItem;
+  oss: IOperationSchemaData;
+}
+
+/**
+ * Represents {@link IOperation} data, used in setInput process.
+ */
+export interface IInputUpdateDTO extends ITargetOperation {
+  input: LibraryItemID | null;
+}
+
+/**
+ * Represents {@link IOperation} data, used in update process.
+ */
+export interface IOperationUpdateDTO extends ITargetOperation {
+  item_data: {
+    alias: string;
+    title: string;
+    comment: string;
+  };
+  arguments: OperationID[] | undefined;
+  substitutions: ICstSubstitute[] | undefined;
+}
+
+/**
+ * Represents data, used relocating {@link IConstituenta}s between {@link ILibraryItem}s.
+ */
+export interface ICstRelocateDTO {
+  destination: LibraryItemID;
+  items: ConstituentaID[];
+}
+
+export const ossApi = {
+  baseKey: 'library',
+
+  getOssQueryOptions: ({ itemID }: { itemID?: LibraryItemID }) => {
+    return queryOptions({
+      queryKey: [ossApi.baseKey, 'item', itemID],
+      staleTime: DELAYS.staleShort,
+      queryFn: meta =>
+        !itemID
+          ? undefined
+          : axiosInstance
+              .get<IOperationSchemaData>(`/api/oss/${itemID}/details`, {
+                signal: meta.signal
+              })
+              .then(response => response.data)
+    });
+  },
+
+  updatePositions: (data: { itemID: LibraryItemID; positions: IOperationPosition[] }) =>
+    axiosInstance //
+      .patch(`/api/oss/${data.itemID}/update-positions`, { positions: data.positions }),
+  operationCreate: (data: { itemID: LibraryItemID; data: IOperationCreateDTO }) =>
+    axiosInstance //
+      .post<IOperationCreatedResponse>(`/api/oss/${data.itemID}/create-operation`, data.data)
+      .then(response => response.data),
+  operationDelete: (data: { itemID: LibraryItemID; data: IOperationDeleteDTO }) =>
+    axiosInstance //
+      .patch<IOperationSchemaData>(`/api/oss/${data.itemID}/delete-operation`, data.data)
+      .then(response => response.data),
+  inputCreate: (data: { itemID: LibraryItemID; data: ITargetOperation }) =>
+    axiosInstance //
+      .patch<IInputCreatedResponse>(`/api/oss/${data.itemID}/create-input`, data.data)
+      .then(response => response.data),
+  inputUpdate: (data: { itemID: LibraryItemID; data: IInputUpdateDTO }) =>
+    axiosInstance //
+      .patch<IOperationSchemaData>(`/api/oss/${data.itemID}/set-input`, data.data)
+      .then(response => response.data),
+  operationUpdate: (data: { itemID: LibraryItemID; data: IOperationUpdateDTO }) =>
+    axiosInstance //
+      .patch<IOperationSchemaData>(`/api/oss/${data.itemID}/update-operation`, data.data)
+      .then(response => response.data),
+  operationExecute: (data: { itemID: LibraryItemID; data: ITargetOperation }) =>
+    axiosInstance //
+      .post<IOperationSchemaData>(`/api/oss/${data.itemID}/execute-operation`, data.data)
+      .then(response => response.data),
+
+  relocateConstituents: (data: { itemID: LibraryItemID; data: ICstRelocateDTO }) =>
+    axiosInstance //
+      .post<IOperationSchemaData>(`/api/oss/${data.itemID}/relocate-constituents`, data.data)
+      .then(response => response.data),
+  getPredecessor: (data: ITargetCst) =>
+    axiosInstance //
+      .post<IConstituentaReference>(`/api/oss/get-predecessor`, data)
+      .then(response => response.data)
+};
diff --git a/rsconcept/frontend/src/backend/oss/useFindPredecessor.tsx b/rsconcept/frontend/src/backend/oss/useFindPredecessor.tsx
new file mode 100644
index 00000000..7e5527f5
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useFindPredecessor.tsx
@@ -0,0 +1,19 @@
+import { useMutation } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { IConstituentaReference, ITargetCst } from '@/models/rsform';
+
+import { ossApi } from './api';
+
+export const useFindPredecessor = () => {
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'find-predecessor'],
+    mutationFn: ossApi.getPredecessor
+  });
+  return {
+    findPredecessor: (
+      data: ITargetCst, //
+      onSuccess?: DataCallback<IConstituentaReference>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss/useInputCreate.tsx b/rsconcept/frontend/src/backend/oss/useInputCreate.tsx
new file mode 100644
index 00000000..b92c0c50
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useInputCreate.tsx
@@ -0,0 +1,28 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { libraryApi } from '@/backend/library/api';
+import { ILibraryItem, LibraryItemID } from '@/models/library';
+
+import { DataCallback } from '../apiTransport';
+import { ITargetOperation, ossApi } from './api';
+
+export const useInputCreate = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'input-create'],
+    mutationFn: ossApi.inputCreate,
+    onSuccess: async data => {
+      client.setQueryData([ossApi.getOssQueryOptions({ itemID: data.oss.id }).queryKey], data.oss);
+      await client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] });
+    }
+  });
+  return {
+    inputCreate: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ITargetOperation;
+      },
+      onSuccess?: DataCallback<ILibraryItem>
+    ) => mutation.mutate(data, { onSuccess: response => onSuccess?.(response.new_schema) })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss/useInputUpdate.tsx b/rsconcept/frontend/src/backend/oss/useInputUpdate.tsx
new file mode 100644
index 00000000..03e59114
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useInputUpdate.tsx
@@ -0,0 +1,27 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { libraryApi } from '@/backend/library/api';
+import { LibraryItemID } from '@/models/library';
+
+import { IInputUpdateDTO, ossApi } from './api';
+
+export const useInputUpdate = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'input-update'],
+    mutationFn: ossApi.inputUpdate,
+    onSuccess: async data => {
+      client.setQueryData([ossApi.getOssQueryOptions({ itemID: data.id }).queryKey], data);
+      await client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] });
+    }
+  });
+  return {
+    inputUpdate: (
+      data: {
+        itemID: LibraryItemID; //
+        data: IInputUpdateDTO;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss/useIsProcessingOss.tsx b/rsconcept/frontend/src/backend/oss/useIsProcessingOss.tsx
new file mode 100644
index 00000000..eabf01fb
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useIsProcessingOss.tsx
@@ -0,0 +1,11 @@
+import { useIsMutating } from '@tanstack/react-query';
+
+import { libraryApi } from '@/backend/library/api';
+
+import { ossApi } from './api';
+
+export const useIsProcessingOss = () => {
+  const countLibrary = useIsMutating({ mutationKey: [libraryApi.baseKey] });
+  const countOss = useIsMutating({ mutationKey: [ossApi.baseKey] });
+  return countLibrary + countOss !== 0;
+};
diff --git a/rsconcept/frontend/src/backend/oss/useOSS.tsx b/rsconcept/frontend/src/backend/oss/useOSS.tsx
new file mode 100644
index 00000000..6a99dad4
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useOSS.tsx
@@ -0,0 +1,47 @@
+import { useQuery, useQueryClient, useSuspenseQuery } from '@tanstack/react-query';
+
+import { LibraryItemID } from '@/models/library';
+import { IOperationSchema, IOperationSchemaData } from '@/models/oss';
+import { OssLoader } from '@/models/OssLoader';
+
+import { useLibrary, useLibrarySuspense } from '@/backend/library/useLibrary';
+import { ossApi } from './api';
+
+export function useOss({ itemID }: { itemID?: LibraryItemID }) {
+  const { items: libraryItems, isLoading: libraryLoading } = useLibrary();
+  const { data, isLoading, error } = useQuery({
+    ...ossApi.getOssQueryOptions({ itemID })
+  });
+
+  const schema = data && !libraryLoading ? new OssLoader(data, libraryItems).produceOSS() : undefined;
+  return { schema: schema, isLoading: isLoading || libraryLoading, error: error };
+}
+
+export function useOssSuspense({ itemID }: { itemID?: LibraryItemID }) {
+  const { items: libraryItems } = useLibrarySuspense();
+  const { data } = useSuspenseQuery({
+    ...ossApi.getOssQueryOptions({ itemID })
+  });
+  const schema = data ? new OssLoader(data, libraryItems).produceOSS() : undefined;
+  return { schema };
+}
+
+export function useOssUpdate({ itemID }: { itemID?: LibraryItemID }) {
+  const { items: libraryItems } = useLibrary();
+  const client = useQueryClient();
+  const queryKey = [ossApi.getOssQueryOptions({ itemID }).queryKey];
+  return {
+    update: (data: IOperationSchemaData) =>
+      client.setQueryData(queryKey, new OssLoader(data, libraryItems).produceOSS()),
+    partialUpdate: (data: Partial<IOperationSchema>) =>
+      client.setQueryData(queryKey, (prev: IOperationSchema) => (prev ? { ...prev, ...data } : prev))
+  };
+}
+
+export function useOssInvalidate({ itemID }: { itemID?: LibraryItemID }) {
+  const client = useQueryClient();
+  const queryKey = [ossApi.getOssQueryOptions({ itemID }).queryKey];
+  return {
+    invalidate: () => client.invalidateQueries({ queryKey })
+  };
+}
diff --git a/rsconcept/frontend/src/backend/oss/useOperationCreate.tsx b/rsconcept/frontend/src/backend/oss/useOperationCreate.tsx
new file mode 100644
index 00000000..84bf6f9b
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useOperationCreate.tsx
@@ -0,0 +1,30 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { IOperationData } from '@/models/oss';
+
+import { IOperationCreateDTO, ossApi } from './api';
+
+export const useOperationCreate = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'operation-create'],
+    mutationFn: ossApi.operationCreate,
+    onSuccess: data => {
+      client.setQueryData([ossApi.getOssQueryOptions({ itemID: data.oss.id }).queryKey], data.oss);
+      updateTimestamp(data.oss.id);
+    }
+  });
+  return {
+    operationCreate: (
+      data: {
+        itemID: LibraryItemID; //
+        data: IOperationCreateDTO;
+      },
+      onSuccess?: DataCallback<IOperationData>
+    ) => mutation.mutate(data, { onSuccess: response => onSuccess?.(response.new_operation) })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss/useOperationDelete.tsx b/rsconcept/frontend/src/backend/oss/useOperationDelete.tsx
new file mode 100644
index 00000000..9ec316b4
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useOperationDelete.tsx
@@ -0,0 +1,27 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { libraryApi } from '@/backend/library/api';
+import { LibraryItemID } from '@/models/library';
+
+import { IOperationDeleteDTO, ossApi } from './api';
+
+export const useOperationDelete = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'operation-delete'],
+    mutationFn: ossApi.operationDelete,
+    onSuccess: async data => {
+      client.setQueryData([ossApi.getOssQueryOptions({ itemID: data.id }).queryKey], data);
+      await client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] });
+    }
+  });
+  return {
+    operationDelete: (
+      data: {
+        itemID: LibraryItemID; //
+        data: IOperationDeleteDTO;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss/useOperationExecute.tsx b/rsconcept/frontend/src/backend/oss/useOperationExecute.tsx
new file mode 100644
index 00000000..a618d21f
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useOperationExecute.tsx
@@ -0,0 +1,27 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { libraryApi } from '@/backend/library/api';
+import { LibraryItemID } from '@/models/library';
+
+import { ITargetOperation, ossApi } from './api';
+
+export const useOperationExecute = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'operation-execute'],
+    mutationFn: ossApi.operationExecute,
+    onSuccess: async data => {
+      client.setQueryData([ossApi.getOssQueryOptions({ itemID: data.id }).queryKey], data);
+      await client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] });
+    }
+  });
+  return {
+    operationExecute: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ITargetOperation;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss/useOperationUpdate.tsx b/rsconcept/frontend/src/backend/oss/useOperationUpdate.tsx
new file mode 100644
index 00000000..340b19ef
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useOperationUpdate.tsx
@@ -0,0 +1,27 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { libraryApi } from '@/backend/library/api';
+import { LibraryItemID } from '@/models/library';
+
+import { IOperationUpdateDTO, ossApi } from './api';
+
+export const useOperationUpdate = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'operation-update'],
+    mutationFn: ossApi.operationUpdate,
+    onSuccess: async data => {
+      client.setQueryData([ossApi.getOssQueryOptions({ itemID: data.id }).queryKey], data);
+      await client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] });
+    }
+  });
+  return {
+    operationUpdate: (
+      data: {
+        itemID: LibraryItemID; //
+        data: IOperationUpdateDTO;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss/useRelocateConstituents.tsx b/rsconcept/frontend/src/backend/oss/useRelocateConstituents.tsx
new file mode 100644
index 00000000..374ccbb3
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useRelocateConstituents.tsx
@@ -0,0 +1,27 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { libraryApi } from '@/backend/library/api';
+import { LibraryItemID } from '@/models/library';
+
+import { ICstRelocateDTO, ossApi } from './api';
+
+export const useRelocateConstituents = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'relocate-constituents'],
+    mutationFn: ossApi.relocateConstituents,
+    onSuccess: async data => {
+      client.setQueryData([ossApi.getOssQueryOptions({ itemID: data.id }).queryKey], data);
+      await client.invalidateQueries({ queryKey: [libraryApi.libraryListKey] });
+    }
+  });
+  return {
+    relocateConstituents: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ICstRelocateDTO;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/oss/useUpdatePositions.tsx b/rsconcept/frontend/src/backend/oss/useUpdatePositions.tsx
new file mode 100644
index 00000000..655d7a68
--- /dev/null
+++ b/rsconcept/frontend/src/backend/oss/useUpdatePositions.tsx
@@ -0,0 +1,25 @@
+import { useMutation } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { IOperationPosition } from '@/models/oss';
+
+import { ossApi } from './api';
+
+export const useUpdatePositions = () => {
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [ossApi.baseKey, 'update-positions'],
+    mutationFn: ossApi.updatePositions,
+    onSuccess: (_, variables) => updateTimestamp(variables.itemID)
+  });
+  return {
+    cstDelete: (
+      data: {
+        itemID: LibraryItemID; //
+        positions: IOperationPosition[];
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/queryClient.ts b/rsconcept/frontend/src/backend/queryClient.ts
index ca2b7909..d36b81b0 100644
--- a/rsconcept/frontend/src/backend/queryClient.ts
+++ b/rsconcept/frontend/src/backend/queryClient.ts
@@ -1,6 +1,8 @@
 import { QueryClient } from '@tanstack/react-query';
 import { AxiosError } from 'axios';
 
+import { DELAYS } from './configuration';
+
 declare module '@tanstack/react-query' {
   interface Register {
     defaultError: AxiosError;
@@ -10,8 +12,8 @@ declare module '@tanstack/react-query' {
 export const queryClient = new QueryClient({
   defaultOptions: {
     queries: {
-      staleTime: 5 * 60 * 1000,
-      gcTime: 24 * 60 * 60 * 1000,
+      staleTime: DELAYS.staleDefault,
+      gcTime: DELAYS.garbageCollection,
       retry: 3,
       refetchOnWindowFocus: true,
       refetchOnMount: true,
diff --git a/rsconcept/frontend/src/backend/rsform/api.ts b/rsconcept/frontend/src/backend/rsform/api.ts
new file mode 100644
index 00000000..c4391a62
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/api.ts
@@ -0,0 +1,191 @@
+import { queryOptions } from '@tanstack/react-query';
+
+import { axiosInstance } from '@/backend/axiosInstance';
+import { DELAYS } from '@/backend/configuration';
+import { LibraryItemID, VersionID } from '@/models/library';
+import { ICstSubstitute, ICstSubstitutions } from '@/models/oss';
+import {
+  ConstituentaID,
+  CstType,
+  IConstituentaList,
+  IConstituentaMeta,
+  IRSFormData,
+  ITargetCst,
+  TermForm
+} from '@/models/rsform';
+import { IExpressionParse } from '@/models/rslang';
+
+/**
+ * Represents data, used for uploading {@link IRSForm} as file.
+ */
+export interface IRSFormUploadDTO {
+  itemID: LibraryItemID;
+  load_metadata: boolean;
+  file: File;
+  fileName: string;
+}
+
+/**
+ * Represents {@link IConstituenta} data, used in creation process.
+ */
+export interface ICstCreateDTO {
+  alias: string;
+  cst_type: CstType;
+  definition_raw: string;
+  term_raw: string;
+  convention: string;
+  definition_formal: string;
+  term_forms: TermForm[];
+
+  insert_after: ConstituentaID | null;
+}
+
+/**
+ * Represents data response when creating {@link IConstituenta}.
+ */
+export interface ICstCreatedResponse {
+  new_cst: IConstituentaMeta;
+  schema: IRSFormData;
+}
+
+/**
+ * Represents data, used in updating persistent attributes in {@link IConstituenta}.
+ */
+export interface ICstUpdateDTO {
+  target: ConstituentaID;
+  item_data: {
+    convention?: string;
+    definition_formal?: string;
+    definition_raw?: string;
+    term_raw?: string;
+    term_forms?: TermForm[];
+  };
+}
+
+/**
+ * Represents data, used in renaming {@link IConstituenta}.
+ */
+export interface ICstRenameDTO {
+  alias: string;
+  cst_type: CstType;
+  target: ConstituentaID;
+}
+
+/**
+ * Represents data, used in ordering a list of {@link IConstituenta}.
+ */
+export interface ICstMoveDTO {
+  items: ConstituentaID[];
+  move_to: number; // Note: 0-base index
+}
+
+/**
+ * Represents data response when creating producing structure of {@link IConstituenta}.
+ */
+export interface IProduceStructureResponse {
+  cst_list: ConstituentaID[];
+  schema: IRSFormData;
+}
+
+/**
+ * Represents input data for inline synthesis.
+ */
+export interface IInlineSynthesisDTO {
+  receiver: LibraryItemID;
+  source: LibraryItemID;
+  items: ConstituentaID[];
+  substitutions: ICstSubstitute[];
+}
+
+/**
+ * Represents {@link IConstituenta} data, used for checking expression.
+ */
+export interface ICheckConstituentaDTO {
+  alias: string;
+  cst_type: CstType;
+  definition_formal: string;
+}
+
+export const rsformsApi = {
+  baseKey: 'library',
+
+  getRSFormQueryOptions: ({ itemID, version }: { itemID?: LibraryItemID; version?: VersionID }) => {
+    return queryOptions({
+      queryKey: [rsformsApi.baseKey, 'item', itemID, version ?? ''],
+      staleTime: DELAYS.staleShort,
+      queryFn: meta =>
+        !itemID
+          ? undefined
+          : axiosInstance
+              .get<IRSFormData>(
+                version ? `/api/library/${itemID}/versions/${version}` : `/api/rsforms/${itemID}/details`,
+                {
+                  signal: meta.signal
+                }
+              )
+              .then(response => response.data)
+    });
+  },
+
+  download: ({ itemID, version }: { itemID: LibraryItemID; version?: VersionID }) =>
+    axiosInstance //
+      .get<Blob>(version ? `/api/versions/${version}/export-file` : `/api/rsforms/${itemID}/export-trs`, {
+        responseType: 'blob'
+      })
+      .then(response => response.data),
+  upload: (data: IRSFormUploadDTO) =>
+    axiosInstance //
+      .patch<IRSFormData>(`/api/rsforms/${data.itemID}/load-trs`, data, {
+        headers: {
+          'Content-Type': 'multipart/form-data'
+        }
+      })
+      .then(response => response.data),
+
+  cstCreate: ({ itemID, data }: { itemID: LibraryItemID; data: ICstCreateDTO }) =>
+    axiosInstance //
+      .post<ICstCreatedResponse>(`/api/rsforms/${itemID}/create-cst`, data)
+      .then(response => response.data),
+  cstUpdate: ({ itemID, data }: { itemID: LibraryItemID; data: ICstUpdateDTO }) =>
+    axiosInstance //
+      .patch<IConstituentaMeta>(`/api/rsforms/${itemID}/update-cst`, data)
+      .then(response => response.data),
+  cstDelete: ({ itemID, data }: { itemID: LibraryItemID; data: IConstituentaList }) =>
+    axiosInstance //
+      .patch<IRSFormData>(`/api/rsforms/${itemID}/delete-multiple-cst`, data)
+      .then(response => response.data),
+  cstRename: ({ itemID, data }: { itemID: LibraryItemID; data: ICstRenameDTO }) =>
+    axiosInstance //
+      .patch<ICstCreatedResponse>(`/api/rsforms/${itemID}/rename-cst`, data)
+      .then(response => response.data),
+  cstSubstitute: ({ itemID, data }: { itemID: LibraryItemID; data: ICstSubstitutions }) =>
+    axiosInstance //
+      .patch<IRSFormData>(`/api/rsforms/${itemID}/substitute`, data)
+      .then(response => response.data),
+  cstMove: ({ itemID, data }: { itemID: LibraryItemID; data: ICstMoveDTO }) =>
+    axiosInstance //
+      .patch<IRSFormData>(`/api/rsforms/${itemID}/move-cst`, data)
+      .then(response => response.data),
+
+  produceStructure: ({ itemID, data }: { itemID: LibraryItemID; data: ITargetCst }) =>
+    axiosInstance //
+      .post<IProduceStructureResponse>(`/api/rsforms/${itemID}/produce-structure`, data)
+      .then(response => response.data),
+  inlineSynthesis: ({ itemID, data }: { itemID: LibraryItemID; data: IInlineSynthesisDTO }) =>
+    axiosInstance //
+      .post<IRSFormData>(`/api/rsforms/${itemID}/inline-synthesis`, data)
+      .then(response => response.data),
+  restoreOrder: (itemID: LibraryItemID) =>
+    axiosInstance //
+      .patch<IRSFormData>(`/api/rsforms/${itemID}/restore-order`)
+      .then(response => response.data),
+  resetAliases: (itemID: LibraryItemID) =>
+    axiosInstance //
+      .patch<IRSFormData>(`/api/rsforms/${itemID}/reset-aliases`)
+      .then(response => response.data),
+
+  checkConstituenta: ({ itemID, data }: { itemID: LibraryItemID; data: ICheckConstituentaDTO }) =>
+    axiosInstance //
+      .post<IExpressionParse>(`/api/rsforms/${itemID}/check-constituenta`, data)
+      .then(response => response.data)
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useCheckConstituenta.tsx b/rsconcept/frontend/src/backend/rsform/useCheckConstituenta.tsx
new file mode 100644
index 00000000..f9cf7d9d
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useCheckConstituenta.tsx
@@ -0,0 +1,26 @@
+import { useMutation } from '@tanstack/react-query';
+
+import { LibraryItemID } from '@/models/library';
+import { IExpressionParse } from '@/models/rslang';
+
+import { DataCallback } from '../apiTransport';
+import { ICheckConstituentaDTO, rsformsApi } from './api';
+
+export const useCheckConstituenta = () => {
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'check-constituenta'],
+    mutationFn: rsformsApi.checkConstituenta
+  });
+  return {
+    checkConstituenta: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ICheckConstituentaDTO;
+      },
+      onSuccess?: DataCallback<IExpressionParse>
+    ) => mutation.mutate(data, { onSuccess }),
+    isPending: mutation.isPending,
+    error: mutation.error,
+    reset: mutation.reset
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useCstCreate.tsx b/rsconcept/frontend/src/backend/rsform/useCstCreate.tsx
new file mode 100644
index 00000000..1f069803
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useCstCreate.tsx
@@ -0,0 +1,31 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { IConstituentaMeta } from '@/models/rsform';
+
+import { ICstCreateDTO, rsformsApi } from './api';
+
+export const useCstCreate = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'create-cst'],
+    mutationFn: rsformsApi.cstCreate,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.schema.id }).queryKey], data.schema);
+      updateTimestamp(data.schema.id);
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    cstCreate: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ICstCreateDTO;
+      },
+      onSuccess?: DataCallback<IConstituentaMeta>
+    ) => mutation.mutate(data, { onSuccess: response => onSuccess?.(response.new_cst) })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useCstDelete.tsx b/rsconcept/frontend/src/backend/rsform/useCstDelete.tsx
new file mode 100644
index 00000000..3871015a
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useCstDelete.tsx
@@ -0,0 +1,30 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { IConstituentaList } from '@/models/rsform';
+
+import { rsformsApi } from './api';
+
+export const useCstDelete = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'delete-multiple-cst'],
+    mutationFn: rsformsApi.cstDelete,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey], data);
+      updateTimestamp(data.id);
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    cstDelete: (
+      data: {
+        itemID: LibraryItemID; //
+        data: IConstituentaList;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useCstMove.tsx b/rsconcept/frontend/src/backend/rsform/useCstMove.tsx
new file mode 100644
index 00000000..3f0cb9f8
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useCstMove.tsx
@@ -0,0 +1,29 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+
+import { ICstMoveDTO, rsformsApi } from './api';
+
+export const useCstMove = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'move-cst'],
+    mutationFn: rsformsApi.cstMove,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey], data);
+      updateTimestamp(data.id);
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    cstMove: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ICstMoveDTO;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useCstRename.tsx b/rsconcept/frontend/src/backend/rsform/useCstRename.tsx
new file mode 100644
index 00000000..0d6e627f
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useCstRename.tsx
@@ -0,0 +1,31 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { IConstituentaMeta } from '@/models/rsform';
+
+import { DataCallback } from '../apiTransport';
+import { ICstRenameDTO, rsformsApi } from './api';
+
+export const useCstRename = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'rename-cst'],
+    mutationFn: rsformsApi.cstRename,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.schema.id }).queryKey], data.schema);
+      updateTimestamp(data.schema.id);
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    cstRename: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ICstRenameDTO;
+      },
+      onSuccess?: DataCallback<IConstituentaMeta>
+    ) => mutation.mutate(data, { onSuccess: response => onSuccess?.(response.new_cst) })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useCstSubstitute.tsx b/rsconcept/frontend/src/backend/rsform/useCstSubstitute.tsx
new file mode 100644
index 00000000..fe23e90d
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useCstSubstitute.tsx
@@ -0,0 +1,30 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { ICstSubstitutions } from '@/models/oss';
+
+import { rsformsApi } from './api';
+
+export const useCstSubstitute = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'substitute-cst'],
+    mutationFn: rsformsApi.cstSubstitute,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey], data);
+      updateTimestamp(data.id);
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    cstSubstitute: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ICstSubstitutions;
+      },
+      onSuccess?: () => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useCstUpdate.tsx b/rsconcept/frontend/src/backend/rsform/useCstUpdate.tsx
new file mode 100644
index 00000000..17aa8bd6
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useCstUpdate.tsx
@@ -0,0 +1,33 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { IConstituentaMeta } from '@/models/rsform';
+
+import { ICstUpdateDTO, rsformsApi } from './api';
+
+export const useCstUpdate = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'update-cst'],
+    mutationFn: rsformsApi.cstUpdate,
+    onSuccess: async (_, variables) => {
+      updateTimestamp(variables.itemID);
+      await client.invalidateQueries({
+        queryKey: [rsformsApi.getRSFormQueryOptions({ itemID: variables.itemID }).queryKey]
+      });
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    cstUpdate: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ICstUpdateDTO;
+      },
+      onSuccess?: DataCallback<IConstituentaMeta>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useDownloadRSForm.tsx b/rsconcept/frontend/src/backend/rsform/useDownloadRSForm.tsx
new file mode 100644
index 00000000..53eb9f7b
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useDownloadRSForm.tsx
@@ -0,0 +1,21 @@
+import { useMutation } from '@tanstack/react-query';
+
+import { LibraryItemID, VersionID } from '@/models/library';
+
+import { rsformsApi } from './api';
+
+export const useDownloadRSForm = () => {
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'download'],
+    mutationFn: rsformsApi.download
+  });
+  return {
+    download: (
+      data: {
+        itemID: LibraryItemID; //
+        version?: VersionID;
+      },
+      onSuccess?: (data: Blob) => void
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useInlineSynthesis.tsx b/rsconcept/frontend/src/backend/rsform/useInlineSynthesis.tsx
new file mode 100644
index 00000000..913341ee
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useInlineSynthesis.tsx
@@ -0,0 +1,31 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { IRSFormData } from '@/models/rsform';
+
+import { DataCallback } from '../apiTransport';
+import { IInlineSynthesisDTO, rsformsApi } from './api';
+
+export const useInlineSynthesis = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'inline-synthesis'],
+    mutationFn: rsformsApi.inlineSynthesis,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey], data);
+      updateTimestamp(data.id);
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    inlineSynthesis: (
+      data: {
+        itemID: LibraryItemID; //
+        data: IInlineSynthesisDTO;
+      },
+      onSuccess?: DataCallback<IRSFormData>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useIsProcessingRSForm.tsx b/rsconcept/frontend/src/backend/rsform/useIsProcessingRSForm.tsx
new file mode 100644
index 00000000..48a6a777
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useIsProcessingRSForm.tsx
@@ -0,0 +1,11 @@
+import { useIsMutating } from '@tanstack/react-query';
+
+import { libraryApi } from '@/backend/library/api';
+
+import { rsformsApi } from './api';
+
+export const useIsProcessingRSForm = () => {
+  const countLibrary = useIsMutating({ mutationKey: [libraryApi.baseKey] });
+  const countRsform = useIsMutating({ mutationKey: [rsformsApi.baseKey] });
+  return countLibrary + countRsform !== 0;
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useProduceStructure.tsx b/rsconcept/frontend/src/backend/rsform/useProduceStructure.tsx
new file mode 100644
index 00000000..6df5802c
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useProduceStructure.tsx
@@ -0,0 +1,31 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+import { ConstituentaID, ITargetCst } from '@/models/rsform';
+
+import { rsformsApi } from './api';
+
+export const useProduceStructure = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'produce-structure'],
+    mutationFn: rsformsApi.produceStructure,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.schema.id }).queryKey], data.schema);
+      updateTimestamp(data.schema.id);
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    produceStructure: (
+      data: {
+        itemID: LibraryItemID; //
+        data: ITargetCst;
+      },
+      onSuccess?: DataCallback<ConstituentaID[]>
+    ) => mutation.mutate(data, { onSuccess: response => onSuccess?.(response.cst_list) })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useRSForm.tsx b/rsconcept/frontend/src/backend/rsform/useRSForm.tsx
new file mode 100644
index 00000000..66050a4a
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useRSForm.tsx
@@ -0,0 +1,34 @@
+import { useQuery, useQueryClient, useSuspenseQuery } from '@tanstack/react-query';
+
+import { LibraryItemID, VersionID } from '@/models/library';
+import { IRSForm, IRSFormData } from '@/models/rsform';
+import { RSFormLoader } from '@/models/RSFormLoader';
+
+import { rsformsApi } from './api';
+
+export function useRSForm({ itemID, version }: { itemID?: LibraryItemID; version?: VersionID }) {
+  const { data, isLoading, error } = useQuery({
+    ...rsformsApi.getRSFormQueryOptions({ itemID, version })
+  });
+
+  const schema = data ? new RSFormLoader(data).produceRSForm() : undefined;
+  return { schema, isLoading, error };
+}
+
+export function useRSFormSuspense({ itemID, version }: { itemID?: LibraryItemID; version?: VersionID }) {
+  const { data } = useSuspenseQuery({
+    ...rsformsApi.getRSFormQueryOptions({ itemID, version })
+  });
+  const schema = data ? new RSFormLoader(data).produceRSForm() : undefined;
+  return { schema };
+}
+
+export function useRSFormUpdate({ itemID }: { itemID: LibraryItemID }) {
+  const client = useQueryClient();
+  const queryKey = [rsformsApi.getRSFormQueryOptions({ itemID }).queryKey];
+  return {
+    update: (data: IRSFormData) => client.setQueryData(queryKey, data),
+    partialUpdate: (data: Partial<IRSForm>) =>
+      client.setQueryData(queryKey, (prev: IRSForm) => (prev ? { ...prev, ...data } : prev))
+  };
+}
diff --git a/rsconcept/frontend/src/backend/rsform/useRSForms.tsx b/rsconcept/frontend/src/backend/rsform/useRSForms.tsx
new file mode 100644
index 00000000..deb6804f
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useRSForms.tsx
@@ -0,0 +1,23 @@
+import { useQueries } from '@tanstack/react-query';
+
+import { LibraryItemID } from '@/models/library';
+import { RSFormLoader } from '@/models/RSFormLoader';
+
+import { DELAYS } from '../configuration';
+import { rsformsApi } from './api';
+
+export function useRSForms(itemIDs: LibraryItemID[]) {
+  const results = useQueries({
+    queries: itemIDs.map(itemID => ({
+      ...rsformsApi.getRSFormQueryOptions({ itemID }),
+      enabled: itemIDs.length > 0,
+      staleTime: DELAYS.staleShort
+    }))
+  });
+
+  const schemas = results
+    .map(result => result.data)
+    .filter(data => data !== undefined)
+    .map(data => new RSFormLoader(data).produceRSForm());
+  return schemas;
+}
diff --git a/rsconcept/frontend/src/backend/rsform/useResetAliases.tsx b/rsconcept/frontend/src/backend/rsform/useResetAliases.tsx
new file mode 100644
index 00000000..16801841
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useResetAliases.tsx
@@ -0,0 +1,26 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+
+import { rsformsApi } from './api';
+
+export const useResetAliases = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'reset-aliases'],
+    mutationFn: rsformsApi.resetAliases,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey], data);
+      updateTimestamp(data.id);
+      // TODO: invalidate OSS?
+    }
+  });
+  return {
+    resetAliases: (
+      itemID: LibraryItemID, //
+      onSuccess?: () => void
+    ) => mutation.mutate(itemID, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useRestoreOrder.tsx b/rsconcept/frontend/src/backend/rsform/useRestoreOrder.tsx
new file mode 100644
index 00000000..64dde162
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useRestoreOrder.tsx
@@ -0,0 +1,25 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { useUpdateTimestamp } from '@/backend/library/useUpdateTimestamp';
+import { LibraryItemID } from '@/models/library';
+
+import { rsformsApi } from './api';
+
+export const useRestoreOrder = () => {
+  const client = useQueryClient();
+  const { updateTimestamp } = useUpdateTimestamp();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'restore-order'],
+    mutationFn: rsformsApi.restoreOrder,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey], data);
+      updateTimestamp(data.id);
+    }
+  });
+  return {
+    restoreOrder: (
+      itemID: LibraryItemID, //
+      onSuccess?: () => void
+    ) => mutation.mutate(itemID, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsform/useUploadTRS.tsx b/rsconcept/frontend/src/backend/rsform/useUploadTRS.tsx
new file mode 100644
index 00000000..587f3bdd
--- /dev/null
+++ b/rsconcept/frontend/src/backend/rsform/useUploadTRS.tsx
@@ -0,0 +1,28 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { libraryApi } from '@/backend/library/api';
+import { ILibraryItem } from '@/models/library';
+import { IRSFormData } from '@/models/rsform';
+
+import { IRSFormUploadDTO, rsformsApi } from './api';
+
+export const useUploadTRS = () => {
+  const client = useQueryClient();
+  const mutation = useMutation({
+    mutationKey: [rsformsApi.baseKey, 'load-trs'],
+    mutationFn: rsformsApi.upload,
+    onSuccess: data => {
+      client.setQueryData([rsformsApi.getRSFormQueryOptions({ itemID: data.id }).queryKey], data);
+      client.setQueryData([libraryApi.libraryListKey], (prev: ILibraryItem[] | undefined) =>
+        prev?.map(item => (item.id === data.id ? data : item))
+      );
+    }
+  });
+  return {
+    upload: (
+      data: IRSFormUploadDTO, //
+      onSuccess?: DataCallback<IRSFormData>
+    ) => mutation.mutate(data, { onSuccess })
+  };
+};
diff --git a/rsconcept/frontend/src/backend/rsforms.ts b/rsconcept/frontend/src/backend/rsforms.ts
deleted file mode 100644
index bd2d689e..00000000
--- a/rsconcept/frontend/src/backend/rsforms.ts
+++ /dev/null
@@ -1,158 +0,0 @@
-/**
- * Endpoints: rsforms.
- */
-
-import { ILibraryCreateData, ILibraryItem } from '@/models/library';
-import { ICstSubstituteData } from '@/models/oss';
-import {
-  ICheckConstituentaData,
-  IConstituentaList,
-  IConstituentaMeta,
-  ICstCreateData,
-  ICstCreatedResponse,
-  ICstMovetoData,
-  ICstRenameData,
-  ICstUpdateData,
-  IInlineSynthesisData,
-  IProduceStructureResponse,
-  IRSFormData,
-  IRSFormUploadData,
-  ITargetCst
-} from '@/models/rsform';
-import { IExpressionParse } from '@/models/rslang';
-
-import { AxiosGet, AxiosPatch, AxiosPost, FrontExchange, FrontPull } from './apiTransport';
-
-export function postRSFormFromFile(request: FrontExchange<ILibraryCreateData, ILibraryItem>) {
-  AxiosPost({
-    endpoint: '/api/rsforms/create-detailed',
-    request: request,
-    options: {
-      headers: {
-        'Content-Type': 'multipart/form-data'
-      }
-    }
-  });
-}
-
-export function getRSFormDetails(target: string, version: string, request: FrontPull<IRSFormData>) {
-  if (!version) {
-    AxiosGet({
-      endpoint: `/api/rsforms/${target}/details`,
-      request: request
-    });
-  } else {
-    AxiosGet({
-      endpoint: `/api/library/${target}/versions/${version}`,
-      request: request
-    });
-  }
-}
-
-export function getTRSFile(target: string, version: string, request: FrontPull<Blob>) {
-  if (!version) {
-    AxiosGet({
-      endpoint: `/api/rsforms/${target}/export-trs`,
-      request: request,
-      options: { responseType: 'blob' }
-    });
-  } else {
-    AxiosGet({
-      endpoint: `/api/versions/${version}/export-file`,
-      request: request,
-      options: { responseType: 'blob' }
-    });
-  }
-}
-
-export function postCreateConstituenta(schema: string, request: FrontExchange<ICstCreateData, ICstCreatedResponse>) {
-  AxiosPost({
-    endpoint: `/api/rsforms/${schema}/create-cst`,
-    request: request
-  });
-}
-
-export function patchUpdateConstituenta(schema: string, request: FrontExchange<ICstUpdateData, IConstituentaMeta>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${schema}/update-cst`,
-    request: request
-  });
-}
-
-export function patchDeleteConstituenta(schema: string, request: FrontExchange<IConstituentaList, IRSFormData>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${schema}/delete-multiple-cst`,
-    request: request
-  });
-}
-
-export function patchRenameConstituenta(schema: string, request: FrontExchange<ICstRenameData, ICstCreatedResponse>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${schema}/rename-cst`,
-    request: request
-  });
-}
-
-export function patchProduceStructure(schema: string, request: FrontExchange<ITargetCst, IProduceStructureResponse>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${schema}/produce-structure`,
-    request: request
-  });
-}
-
-export function patchSubstituteConstituents(schema: string, request: FrontExchange<ICstSubstituteData, IRSFormData>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${schema}/substitute`,
-    request: request
-  });
-}
-
-export function patchMoveConstituenta(schema: string, request: FrontExchange<ICstMovetoData, IRSFormData>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${schema}/move-cst`,
-    request: request
-  });
-}
-
-export function postCheckConstituenta(
-  schema: string,
-  request: FrontExchange<ICheckConstituentaData, IExpressionParse>
-) {
-  AxiosPost({
-    endpoint: `/api/rsforms/${schema}/check-constituenta`,
-    request: request
-  });
-}
-
-export function patchResetAliases(target: string, request: FrontPull<IRSFormData>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${target}/reset-aliases`,
-    request: request
-  });
-}
-
-export function patchRestoreOrder(target: string, request: FrontPull<IRSFormData>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${target}/restore-order`,
-    request: request
-  });
-}
-
-export function patchUploadTRS(target: string, request: FrontExchange<IRSFormUploadData, IRSFormData>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/${target}/load-trs`,
-    request: request,
-    options: {
-      headers: {
-        'Content-Type': 'multipart/form-data'
-      }
-    }
-  });
-}
-
-export function patchInlineSynthesis(request: FrontExchange<IInlineSynthesisData, IRSFormData>) {
-  AxiosPatch({
-    endpoint: `/api/rsforms/inline-synthesis`,
-    request: request
-  });
-}
diff --git a/rsconcept/frontend/src/backend/users/api.ts b/rsconcept/frontend/src/backend/users/api.ts
index b20983e9..c1aeb469 100644
--- a/rsconcept/frontend/src/backend/users/api.ts
+++ b/rsconcept/frontend/src/backend/users/api.ts
@@ -1,9 +1,9 @@
 import { queryOptions } from '@tanstack/react-query';
 
+import { axiosInstance } from '@/backend/axiosInstance';
+import { DELAYS } from '@/backend/configuration';
 import { IUser, IUserInfo, IUserProfile, IUserSignupData } from '@/models/user';
 
-import { axiosInstance } from '../apiConfiguration';
-
 /**
  * Represents user data, intended to update user profile in persistent storage.
  */
@@ -14,17 +14,18 @@ export const usersApi = {
   getUsersQueryOptions: () =>
     queryOptions({
       queryKey: [usersApi.baseKey, 'list'],
+      staleTime: DELAYS.staleMedium,
       queryFn: meta =>
         axiosInstance
           .get<IUserInfo[]>('/users/api/active-users', {
             signal: meta.signal
           })
-          .then(response => response.data),
-      placeholderData: []
+          .then(response => response.data)
     }),
   getProfileQueryOptions: () =>
     queryOptions({
       queryKey: [usersApi.baseKey, 'profile'],
+      staleTime: DELAYS.staleShort,
       queryFn: meta =>
         axiosInstance
           .get<IUserProfile>('/users/api/profile', {
@@ -36,5 +37,3 @@ export const usersApi = {
   signup: (data: IUserSignupData) => axiosInstance.post('/users/api/signup', data),
   updateProfile: (data: IUpdateProfileDTO) => axiosInstance.patch('/users/api/profile', data)
 };
-
-//DataCallback<IUserProfile>
diff --git a/rsconcept/frontend/src/backend/users/useSignup.tsx b/rsconcept/frontend/src/backend/users/useSignup.tsx
index 777c6fcf..5065d13b 100644
--- a/rsconcept/frontend/src/backend/users/useSignup.tsx
+++ b/rsconcept/frontend/src/backend/users/useSignup.tsx
@@ -1,20 +1,21 @@
 import { useMutation, useQueryClient } from '@tanstack/react-query';
 
+import { DataCallback } from '@/backend/apiTransport';
 import { usersApi } from '@/backend/users/api';
 import { IUserProfile, IUserSignupData } from '@/models/user';
 
-import { DataCallback } from '../apiTransport';
-
 export const useSignup = () => {
-  const queryClient = useQueryClient();
+  const client = useQueryClient();
   const mutation = useMutation({
     mutationKey: ['signup'],
     mutationFn: usersApi.signup,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: [usersApi.baseKey] })
+    onSuccess: async () => await client.invalidateQueries({ queryKey: [usersApi.baseKey] })
   });
   return {
-    signup: (data: IUserSignupData, onSuccess?: DataCallback<IUserProfile>) =>
-      mutation.mutate(data, { onSuccess: response => onSuccess?.(response.data as IUserProfile) }),
+    signup: (
+      data: IUserSignupData, //
+      onSuccess?: DataCallback<IUserProfile>
+    ) => mutation.mutate(data, { onSuccess: response => onSuccess?.(response.data as IUserProfile) }),
     isPending: mutation.isPending,
     error: mutation.error,
     reset: mutation.reset
diff --git a/rsconcept/frontend/src/backend/users/useUpdateProfile.tsx b/rsconcept/frontend/src/backend/users/useUpdateProfile.tsx
index 051f5ac1..507c1fd6 100644
--- a/rsconcept/frontend/src/backend/users/useUpdateProfile.tsx
+++ b/rsconcept/frontend/src/backend/users/useUpdateProfile.tsx
@@ -1,5 +1,6 @@
 import { useMutation, useQueryClient } from '@tanstack/react-query';
 
+import { DataCallback } from '@/backend/apiTransport';
 import { IUserProfile } from '@/models/user';
 
 import { IUpdateProfileDTO, usersApi } from './api';
@@ -7,15 +8,17 @@ import { IUpdateProfileDTO, usersApi } from './api';
 // TODO: reload users / optimistic update
 
 export const useUpdateProfile = () => {
-  const queryClient = useQueryClient();
+  const client = useQueryClient();
   const mutation = useMutation({
     mutationKey: ['update-profile'],
     mutationFn: usersApi.updateProfile,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: [usersApi.baseKey] })
+    onSuccess: async () => await client.invalidateQueries({ queryKey: [usersApi.baseKey] })
   });
   return {
-    updateProfile: (data: IUpdateProfileDTO, onSuccess?: (newUser: IUserProfile) => void) =>
-      mutation.mutate(data, { onSuccess: response => onSuccess?.(response.data as IUserProfile) }),
+    updateProfile: (
+      data: IUpdateProfileDTO, //
+      onSuccess?: DataCallback<IUserProfile>
+    ) => mutation.mutate(data, { onSuccess: response => onSuccess?.(response.data as IUserProfile) }),
     isPending: mutation.isPending,
     error: mutation.error,
     reset: mutation.reset
diff --git a/rsconcept/frontend/src/backend/users/useUsers.tsx b/rsconcept/frontend/src/backend/users/useUsers.tsx
index d4172871..18222a1c 100644
--- a/rsconcept/frontend/src/backend/users/useUsers.tsx
+++ b/rsconcept/frontend/src/backend/users/useUsers.tsx
@@ -4,8 +4,7 @@ import { usersApi } from './api';
 
 export function useUsersSuspense() {
   const { data: users } = useSuspenseQuery({
-    ...usersApi.getUsersQueryOptions(),
-    initialData: []
+    ...usersApi.getUsersQueryOptions()
   });
   return { users };
 }
diff --git a/rsconcept/frontend/src/backend/versions.ts b/rsconcept/frontend/src/backend/versions.ts
deleted file mode 100644
index e04e5206..00000000
--- a/rsconcept/frontend/src/backend/versions.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-/**
- * Endpoints: versions.
- */
-
-import { IVersionData } from '@/models/library';
-import { IRSFormData } from '@/models/rsform';
-
-import { AxiosDelete, AxiosPatch, FrontAction, FrontPull, FrontPush } from './apiTransport';
-
-export function patchVersion(target: string, request: FrontPush<IVersionData>) {
-  // title: `Version id=${target}`,
-  AxiosPatch({
-    endpoint: `/api/versions/${target}`,
-    request: request
-  });
-}
-
-export function patchRestoreVersion(target: string, request: FrontPull<IRSFormData>) {
-  AxiosPatch({
-    endpoint: `/api/versions/${target}/restore`,
-    request: request
-  });
-}
-
-export function deleteVersion(target: string, request: FrontAction) {
-  AxiosDelete({
-    endpoint: `/api/versions/${target}`,
-    request: request
-  });
-}
diff --git a/rsconcept/frontend/src/components/RSInput/RSInput.tsx b/rsconcept/frontend/src/components/RSInput/RSInput.tsx
index a1791edf..a368e8d4 100644
--- a/rsconcept/frontend/src/components/RSInput/RSInput.tsx
+++ b/rsconcept/frontend/src/components/RSInput/RSInput.tsx
@@ -47,7 +47,7 @@ interface RSInputProps
 const RSInput = forwardRef<ReactCodeMirrorRef, RSInputProps>(
   (
     {
-      id, // prettier: split lines
+      id, //
       label,
       disabled,
       noTooltip,
diff --git a/rsconcept/frontend/src/components/info/BadgeGrammeme.tsx b/rsconcept/frontend/src/components/info/BadgeGrammeme.tsx
index 8dea738d..2ad49f5f 100644
--- a/rsconcept/frontend/src/components/info/BadgeGrammeme.tsx
+++ b/rsconcept/frontend/src/components/info/BadgeGrammeme.tsx
@@ -16,7 +16,7 @@ function BadgeGrammeme({ grammeme }: BadgeGrammemeProps) {
   return (
     <div
       className={clsx(
-        'min-w-[3rem]', // prettier: split lines
+        'min-w-[3rem]', //
         'px-1',
         'border rounded-md',
         'text-sm font-medium text-center whitespace-nowrap'
diff --git a/rsconcept/frontend/src/components/info/InfoCstStatus.tsx b/rsconcept/frontend/src/components/info/InfoCstStatus.tsx
index 73e70375..853c2847 100644
--- a/rsconcept/frontend/src/components/info/InfoCstStatus.tsx
+++ b/rsconcept/frontend/src/components/info/InfoCstStatus.tsx
@@ -19,7 +19,7 @@ function InfoCstStatus({ title }: InfoCstStatusProps) {
           <p key={`${prefixes.cst_status_list}${index}`}>
             <span
               className={clsx(
-                'inline-block', // prettier: split lines
+                'inline-block', //
                 'min-w-[7rem]',
                 'px-1',
                 'border',
diff --git a/rsconcept/frontend/src/components/info/InfoError.tsx b/rsconcept/frontend/src/components/info/InfoError.tsx
index c65e9025..7cfdfc88 100644
--- a/rsconcept/frontend/src/components/info/InfoError.tsx
+++ b/rsconcept/frontend/src/components/info/InfoError.tsx
@@ -5,7 +5,7 @@ import { isResponseHtml } from '@/utils/utils';
 
 import PrettyJson from '../ui/PrettyJSON';
 
-export type ErrorData = string | Error | AxiosError | undefined;
+export type ErrorData = string | Error | AxiosError | undefined | null;
 
 interface InfoErrorProps {
   error: ErrorData;
diff --git a/rsconcept/frontend/src/components/select/PickSchema.tsx b/rsconcept/frontend/src/components/select/PickSchema.tsx
index eb555af8..ffd25b03 100644
--- a/rsconcept/frontend/src/components/select/PickSchema.tsx
+++ b/rsconcept/frontend/src/components/select/PickSchema.tsx
@@ -4,7 +4,6 @@ import { useIntl } from 'react-intl';
 
 import DataTable, { createColumnHelper, IConditionalStyle } from '@/components/ui/DataTable';
 import SearchBar from '@/components/ui/SearchBar';
-import { useLibrary } from '@/context/LibraryContext';
 import useDropdown from '@/hooks/useDropdown';
 import { ILibraryItem, LibraryItemID, LibraryItemType } from '@/models/library';
 import { matchLibraryItem } from '@/models/libraryAPI';
@@ -45,8 +44,6 @@ function PickSchema({
   ...restProps
 }: PickSchemaProps) {
   const intl = useIntl();
-  const { folders } = useLibrary();
-
   const [filterText, setFilterText] = useState(initialFilter);
   const [filterLocation, setFilterLocation] = useState('');
   const [filtered, setFiltered] = useState<ILibraryItem[]>([]);
@@ -128,7 +125,6 @@ function PickSchema({
           />
           <Dropdown isOpen={locationMenu.isOpen} stretchLeft className='w-[20rem] h-[12.5rem] z-modalTooltip mt-0'>
             <SelectLocation
-              folderTree={folders}
               value={filterLocation}
               prefix={prefixes.folders_list}
               dense
diff --git a/rsconcept/frontend/src/components/select/SelectLocation.tsx b/rsconcept/frontend/src/components/select/SelectLocation.tsx
index 1ef88716..58f14a48 100644
--- a/rsconcept/frontend/src/components/select/SelectLocation.tsx
+++ b/rsconcept/frontend/src/components/select/SelectLocation.tsx
@@ -3,7 +3,8 @@
 import clsx from 'clsx';
 import { useEffect, useState } from 'react';
 
-import { FolderNode, FolderTree } from '@/models/FolderTree';
+import { useFolders } from '@/backend/library/useFolders';
+import { FolderNode } from '@/models/FolderTree';
 import { labelFolderNode } from '@/utils/labels';
 
 import { IconFolder, IconFolderClosed, IconFolderEmpty, IconFolderOpened } from '../Icons';
@@ -12,15 +13,15 @@ import MiniButton from '../ui/MiniButton';
 
 interface SelectLocationProps extends CProps.Styling {
   value: string;
-  folderTree: FolderTree;
   prefix: string;
   dense?: boolean;
   onClick: (event: CProps.EventMouse, target: FolderNode) => void;
 }
 
-function SelectLocation({ value, folderTree, dense, prefix, onClick, className, style }: SelectLocationProps) {
-  const activeNode = folderTree.at(value);
-  const items = folderTree.getTree();
+function SelectLocation({ value, dense, prefix, onClick, className, style }: SelectLocationProps) {
+  const { folders } = useFolders();
+  const activeNode = folders.at(value);
+  const items = folders.getTree();
   const [folded, setFolded] = useState<FolderNode[]>(items);
 
   useEffect(() => {
diff --git a/rsconcept/frontend/src/components/select/SelectLocationContext.tsx b/rsconcept/frontend/src/components/select/SelectLocationContext.tsx
index 65af7646..9f6d8c9d 100644
--- a/rsconcept/frontend/src/components/select/SelectLocationContext.tsx
+++ b/rsconcept/frontend/src/components/select/SelectLocationContext.tsx
@@ -4,7 +4,6 @@ import clsx from 'clsx';
 import { useCallback } from 'react';
 
 import useDropdown from '@/hooks/useDropdown';
-import { FolderTree } from '@/models/FolderTree';
 import { prefixes } from '@/utils/constants';
 
 import { IconFolderTree } from '../Icons';
@@ -16,7 +15,6 @@ import SelectLocation from './SelectLocation';
 interface SelectLocationContextProps extends CProps.Styling {
   value: string;
   title?: string;
-  folderTree: FolderTree;
   stretchTop?: boolean;
 
   onChange: (newValue: string) => void;
@@ -25,7 +23,6 @@ interface SelectLocationContextProps extends CProps.Styling {
 function SelectLocationContext({
   value,
   title = 'Проводник...',
-  folderTree,
   onChange,
   className,
   style
@@ -56,7 +53,6 @@ function SelectLocationContext({
         style={style}
       >
         <SelectLocation
-          folderTree={folderTree}
           value={value}
           prefix={prefixes.folders_list}
           dense
diff --git a/rsconcept/frontend/src/components/ui/Checkbox.tsx b/rsconcept/frontend/src/components/ui/Checkbox.tsx
index 5b221673..f6328d0e 100644
--- a/rsconcept/frontend/src/components/ui/Checkbox.tsx
+++ b/rsconcept/frontend/src/components/ui/Checkbox.tsx
@@ -48,7 +48,7 @@ function Checkbox({
     <button
       type='button'
       className={clsx(
-        'flex items-center gap-2', // prettier: split lines
+        'flex items-center gap-2', //
         'outline-none',
         'focus-frame',
         cursor,
@@ -64,7 +64,7 @@ function Checkbox({
     >
       <div
         className={clsx(
-          'max-w-[1rem] min-w-[1rem] h-4', // prettier: split lines
+          'max-w-[1rem] min-w-[1rem] h-4', //
           'pt-[0.1rem] pl-[0.1rem]',
           'border rounded-sm',
           'cc-animate-color',
diff --git a/rsconcept/frontend/src/components/ui/CheckboxTristate.tsx b/rsconcept/frontend/src/components/ui/CheckboxTristate.tsx
index b49ec701..6329c716 100644
--- a/rsconcept/frontend/src/components/ui/CheckboxTristate.tsx
+++ b/rsconcept/frontend/src/components/ui/CheckboxTristate.tsx
@@ -49,7 +49,7 @@ function CheckboxTristate({
     <button
       type='button'
       className={clsx(
-        'flex items-center gap-2', // prettier: split lines
+        'flex items-center gap-2', //
         'outline-none',
         'focus-frame',
         cursor,
@@ -65,7 +65,7 @@ function CheckboxTristate({
     >
       <div
         className={clsx(
-          'w-4 h-4', // prettier: split lines
+          'w-4 h-4', //
           'pt-[0.1rem] pl-[0.1rem]',
           'border rounded-sm',
           'cc-animate-color',
diff --git a/rsconcept/frontend/src/components/ui/PrettyJSON.tsx b/rsconcept/frontend/src/components/ui/PrettyJSON.tsx
index d0d4fc1e..898f33f9 100644
--- a/rsconcept/frontend/src/components/ui/PrettyJSON.tsx
+++ b/rsconcept/frontend/src/components/ui/PrettyJSON.tsx
@@ -6,7 +6,8 @@ interface PrettyJsonProps {
  * Displays JSON data in a formatted string.
  */
 function PrettyJson({ data }: PrettyJsonProps) {
-  return <pre>{JSON.stringify(data, null, 2)}</pre>;
+  const text = JSON.stringify(data, null, 2);
+  return <pre>{text === '{}' ? '' : text}</pre>;
 }
 
 export default PrettyJson;
diff --git a/rsconcept/frontend/src/components/wrap/ExpectedAnonymous.tsx b/rsconcept/frontend/src/components/wrap/ExpectedAnonymous.tsx
index 6889419d..c5fb7e37 100644
--- a/rsconcept/frontend/src/components/wrap/ExpectedAnonymous.tsx
+++ b/rsconcept/frontend/src/components/wrap/ExpectedAnonymous.tsx
@@ -1,7 +1,7 @@
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
 import { useLogout } from '@/backend/auth/useLogout';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 
 import TextURL from '../ui/TextURL';
 
diff --git a/rsconcept/frontend/src/context/LibraryContext.tsx b/rsconcept/frontend/src/context/LibraryContext.tsx
deleted file mode 100644
index e212f467..00000000
--- a/rsconcept/frontend/src/context/LibraryContext.tsx
+++ /dev/null
@@ -1,322 +0,0 @@
-'use client';
-
-import { createContext, useCallback, useContext, useEffect, useMemo, useState } from 'react';
-
-import { DataCallback } from '@/backend/apiTransport';
-import { useAuth } from '@/backend/auth/useAuth';
-import {
-  deleteLibraryItem,
-  getAdminLibrary,
-  getLibrary,
-  getTemplates,
-  patchRenameLocation,
-  postCloneLibraryItem,
-  postCreateLibraryItem
-} from '@/backend/library';
-import { getRSFormDetails, postRSFormFromFile } from '@/backend/rsforms';
-import { ErrorData } from '@/components/info/InfoError';
-import { FolderTree } from '@/models/FolderTree';
-import { ILibraryItem, IRenameLocationData, LibraryItemID, LocationHead } from '@/models/library';
-import { ILibraryCreateData } from '@/models/library';
-import { matchLibraryItem, matchLibraryItemLocation } from '@/models/libraryAPI';
-import { ILibraryFilter } from '@/models/miscellaneous';
-import { IRSForm, IRSFormCloneData, IRSFormData } from '@/models/rsform';
-import { RSFormLoader } from '@/models/RSFormLoader';
-import { usePreferencesStore } from '@/stores/preferences';
-import { contextOutsideScope } from '@/utils/labels';
-
-interface ILibraryContext {
-  items: ILibraryItem[];
-  templates: ILibraryItem[];
-  folders: FolderTree;
-
-  loading: boolean;
-  loadingError: ErrorData;
-  setLoadingError: (error: ErrorData) => void;
-
-  processing: boolean;
-  processingError: ErrorData;
-  setProcessingError: (error: ErrorData) => void;
-
-  reloadItems: (callback?: () => void) => void;
-
-  applyFilter: (params: ILibraryFilter) => ILibraryItem[];
-  retrieveTemplate: (templateID: LibraryItemID, callback: (schema: IRSForm) => void) => void;
-  createItem: (data: ILibraryCreateData, callback?: DataCallback<ILibraryItem>) => void;
-  cloneItem: (target: LibraryItemID, data: IRSFormCloneData, callback: DataCallback<IRSFormData>) => void;
-  destroyItem: (target: LibraryItemID, callback?: () => void) => void;
-  renameLocation: (data: IRenameLocationData, callback?: () => void) => void;
-
-  localUpdateItem: (data: Partial<ILibraryItem>) => void;
-  localUpdateTimestamp: (target: LibraryItemID) => void;
-}
-
-const LibraryContext = createContext<ILibraryContext | null>(null);
-export const useLibrary = (): ILibraryContext => {
-  const context = useContext(LibraryContext);
-  if (context === null) {
-    throw new Error(contextOutsideScope('useLibrary', 'LibraryState'));
-  }
-  return context;
-};
-
-export const LibraryState = ({ children }: React.PropsWithChildren) => {
-  const { user, isLoading: userLoading } = useAuth();
-  const adminMode = usePreferencesStore(state => state.adminMode);
-
-  const [items, setItems] = useState<ILibraryItem[]>([]);
-  const [templates, setTemplates] = useState<ILibraryItem[]>([]);
-  const [loading, setLoading] = useState(true);
-  const [processing, setProcessing] = useState(false);
-  const [loadingError, setLoadingError] = useState<ErrorData>(undefined);
-  const [processingError, setProcessingError] = useState<ErrorData>(undefined);
-  const [cachedTemplates, setCachedTemplates] = useState<IRSForm[]>([]);
-
-  const folders = useMemo(() => {
-    const result = new FolderTree();
-    result.addPath(LocationHead.USER, 0);
-    result.addPath(LocationHead.COMMON, 0);
-    result.addPath(LocationHead.LIBRARY, 0);
-    result.addPath(LocationHead.PROJECTS, 0);
-    items.forEach(item => result.addPath(item.location));
-    return result;
-  }, [items]);
-
-  const applyFilter = useCallback(
-    (filter: ILibraryFilter) => {
-      let result = items;
-      if (!filter.folderMode && filter.head) {
-        result = result.filter(item => item.location.startsWith(filter.head!));
-      }
-      if (filter.folderMode && filter.location) {
-        if (filter.subfolders) {
-          result = result.filter(
-            item => item.location == filter.location || item.location.startsWith(filter.location! + '/')
-          );
-        } else {
-          result = result.filter(item => item.location == filter.location);
-        }
-      }
-      if (filter.type) {
-        result = result.filter(item => item.item_type === filter.type);
-      }
-      if (filter.isVisible !== undefined) {
-        result = result.filter(item => filter.isVisible === item.visible);
-      }
-      if (filter.isOwned !== undefined) {
-        result = result.filter(item => filter.isOwned === (item.owner === user?.id));
-      }
-      if (filter.isEditor !== undefined) {
-        result = result.filter(item => filter.isEditor == user?.editor.includes(item.id));
-      }
-      if (filter.filterUser !== undefined) {
-        result = result.filter(item => filter.filterUser === item.owner);
-      }
-      if (!filter.folderMode && filter.path) {
-        result = result.filter(item => matchLibraryItemLocation(item, filter.path!));
-      }
-      if (filter.query) {
-        result = result.filter(item => matchLibraryItem(item, filter.query!));
-      }
-      return result;
-    },
-    [items, user]
-  );
-
-  const retrieveTemplate = useCallback(
-    (templateID: LibraryItemID, callback: (schema: IRSForm) => void) => {
-      const cached = cachedTemplates.find(schema => schema.id == templateID);
-      if (cached) {
-        callback(cached);
-        return;
-      }
-      setProcessingError(undefined);
-      getRSFormDetails(String(templateID), '', {
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: data => {
-          const schema = new RSFormLoader(data).produceRSForm();
-          setCachedTemplates(prev => [...prev, schema]);
-          callback(schema);
-        }
-      });
-    },
-    [cachedTemplates]
-  );
-
-  const reloadItems = useCallback(
-    (callback?: () => void) => {
-      setItems([]);
-      setLoadingError(undefined);
-      if (user?.is_staff && adminMode) {
-        getAdminLibrary({
-          setLoading: setLoading,
-          showError: true,
-          onError: setLoadingError,
-          onSuccess: newData => {
-            setItems(newData);
-            callback?.();
-          }
-        });
-      } else {
-        getLibrary({
-          setLoading: setLoading,
-          showError: true,
-          onError: setLoadingError,
-          onSuccess: newData => {
-            setItems(newData);
-            callback?.();
-          }
-        });
-      }
-    },
-    [user, adminMode]
-  );
-
-  const reloadTemplates = useCallback(() => {
-    setTemplates([]);
-    getTemplates({
-      setLoading: setProcessing,
-      onError: setProcessingError,
-      showError: true,
-      onSuccess: newData => setTemplates(newData)
-    });
-  }, []);
-
-  useEffect(() => {
-    if (!userLoading) {
-      reloadItems();
-    }
-  }, [reloadItems, userLoading]);
-
-  useEffect(() => {
-    reloadTemplates();
-  }, [reloadTemplates]);
-
-  const localUpdateItem = useCallback(
-    (data: Partial<ILibraryItem>) => {
-      setItems(prev => prev.map(item => (item.id === data.id ? { ...item, ...data } : item)));
-    },
-    [setItems]
-  );
-
-  const localUpdateTimestamp = useCallback(
-    (target: LibraryItemID) => {
-      setItems(prev => prev.map(item => (item.id === target ? { ...item, time_update: Date() } : item)));
-    },
-    [setItems]
-  );
-
-  const createItem = useCallback(
-    (data: ILibraryCreateData, callback?: DataCallback<ILibraryItem>) => {
-      const onSuccess = (newSchema: ILibraryItem) =>
-        reloadItems(() => {
-          callback?.(newSchema);
-        });
-      setProcessingError(undefined);
-      if (data.file) {
-        postRSFormFromFile({
-          data: data,
-          showError: true,
-          setLoading: setProcessing,
-          onError: setProcessingError,
-          onSuccess: onSuccess
-        });
-      } else {
-        postCreateLibraryItem({
-          data: data,
-          showError: true,
-          setLoading: setProcessing,
-          onError: setProcessingError,
-          onSuccess: onSuccess
-        });
-      }
-    },
-    [reloadItems]
-  );
-
-  const destroyItem = useCallback(
-    (target: LibraryItemID, callback?: () => void) => {
-      setProcessingError(undefined);
-      deleteLibraryItem(String(target), {
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () =>
-          reloadItems(() => {
-            callback?.();
-          })
-      });
-    },
-    [reloadItems]
-  );
-
-  const cloneItem = useCallback(
-    (target: LibraryItemID, data: IRSFormCloneData, callback: DataCallback<IRSFormData>) => {
-      if (!user) {
-        return;
-      }
-      setProcessingError(undefined);
-      postCloneLibraryItem(String(target), {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newSchema =>
-          reloadItems(() => {
-            callback?.(newSchema);
-          })
-      });
-    },
-    [reloadItems, user]
-  );
-
-  const renameLocation = useCallback(
-    (data: IRenameLocationData, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchRenameLocation({
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () =>
-          reloadItems(() => {
-            callback?.();
-          })
-      });
-    },
-    [reloadItems]
-  );
-
-  return (
-    <LibraryContext
-      value={{
-        items,
-        folders,
-        templates,
-
-        loading,
-        loadingError,
-        setLoadingError,
-        reloadItems,
-
-        processing,
-        processingError,
-        setProcessingError,
-
-        applyFilter,
-        createItem,
-        cloneItem,
-        destroyItem,
-        renameLocation,
-
-        retrieveTemplate,
-        localUpdateItem,
-        localUpdateTimestamp
-      }}
-    >
-      {children}
-    </LibraryContext>
-  );
-};
diff --git a/rsconcept/frontend/src/context/OssContext.tsx b/rsconcept/frontend/src/context/OssContext.tsx
deleted file mode 100644
index 9bc96fae..00000000
--- a/rsconcept/frontend/src/context/OssContext.tsx
+++ /dev/null
@@ -1,390 +0,0 @@
-'use client';
-
-import { createContext, useCallback, useContext, useEffect, useMemo, useState } from 'react';
-
-import { DataCallback } from '@/backend/apiTransport';
-import { useAuth } from '@/backend/auth/useAuth';
-import {
-  patchLibraryItem,
-  patchSetAccessPolicy,
-  patchSetEditors,
-  patchSetLocation,
-  patchSetOwner
-} from '@/backend/library';
-import {
-  patchCreateInput,
-  patchDeleteOperation,
-  patchSetInput,
-  patchUpdateOperation,
-  patchUpdatePositions,
-  postCreateOperation,
-  postExecuteOperation,
-  postRelocateConstituents
-} from '@/backend/oss';
-import { type ErrorData } from '@/components/info/InfoError';
-import { AccessPolicy, ILibraryItem } from '@/models/library';
-import { ILibraryUpdateData } from '@/models/library';
-import {
-  ICstRelocateData,
-  IOperationCreateData,
-  IOperationData,
-  IOperationDeleteData,
-  IOperationSchema,
-  IOperationSchemaData,
-  IOperationSetInputData,
-  IOperationUpdateData,
-  IPositionsData,
-  ITargetOperation
-} from '@/models/oss';
-import { UserID } from '@/models/user';
-import { contextOutsideScope } from '@/utils/labels';
-
-import { useGlobalOss } from './GlobalOssContext';
-import { useLibrary } from './LibraryContext';
-
-interface IOssContext {
-  schema?: IOperationSchema;
-  itemID: string;
-
-  loading: boolean;
-  loadingError: ErrorData;
-  processing: boolean;
-  processingError: ErrorData;
-
-  isOwned: boolean;
-
-  update: (data: ILibraryUpdateData, callback?: DataCallback<ILibraryItem>) => void;
-
-  setOwner: (newOwner: UserID, callback?: () => void) => void;
-  setAccessPolicy: (newPolicy: AccessPolicy, callback?: () => void) => void;
-  setLocation: (newLocation: string, callback?: () => void) => void;
-  setEditors: (newEditors: UserID[], callback?: () => void) => void;
-
-  savePositions: (data: IPositionsData, callback?: () => void) => void;
-  createOperation: (data: IOperationCreateData, callback?: DataCallback<IOperationData>) => void;
-  deleteOperation: (data: IOperationDeleteData, callback?: () => void) => void;
-  createInput: (data: ITargetOperation, callback?: DataCallback<ILibraryItem>) => void;
-  setInput: (data: IOperationSetInputData, callback?: () => void) => void;
-  updateOperation: (data: IOperationUpdateData, callback?: () => void) => void;
-  executeOperation: (data: ITargetOperation, callback?: () => void) => void;
-  relocateConstituents: (data: ICstRelocateData, callback?: () => void) => void;
-}
-
-const OssContext = createContext<IOssContext | null>(null);
-export const useOSS = () => {
-  const context = useContext(OssContext);
-  if (context === null) {
-    throw new Error(contextOutsideScope('useOSS', 'OssState'));
-  }
-  return context;
-};
-
-interface OssStateProps {
-  itemID: string;
-}
-
-export const OssState = ({ itemID, children }: React.PropsWithChildren<OssStateProps>) => {
-  const library = useLibrary();
-  const ossData = useGlobalOss();
-  const { user } = useAuth();
-  const [processing, setProcessing] = useState(false);
-  const [processingError, setProcessingError] = useState<ErrorData>(undefined);
-
-  const isOwned = useMemo(() => {
-    return user?.id === ossData.schema?.owner || false;
-  }, [user, ossData.schema?.owner]);
-
-  useEffect(() => {
-    ossData.setID(itemID);
-  }, [itemID, ossData]);
-
-  const update = useCallback(
-    (data: ILibraryUpdateData, callback?: DataCallback<ILibraryItem>) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchLibraryItem(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          const fullData: IOperationSchemaData = Object.assign(ossData.schema!, newData);
-          ossData.setData(fullData);
-          library.localUpdateItem(newData);
-          callback?.(newData);
-        }
-      });
-    },
-    [itemID, library, ossData]
-  );
-
-  const setOwner = useCallback(
-    (newOwner: UserID, callback?: () => void) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchSetOwner(itemID, {
-        data: { user: newOwner },
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          ossData.partialUpdate({ owner: newOwner });
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [itemID, ossData, library]
-  );
-
-  const setAccessPolicy = useCallback(
-    (newPolicy: AccessPolicy, callback?: () => void) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchSetAccessPolicy(itemID, {
-        data: {
-          access_policy: newPolicy
-        },
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          ossData.partialUpdate({ access_policy: newPolicy });
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [itemID, ossData, library]
-  );
-
-  const setLocation = useCallback(
-    (newLocation: string, callback?: () => void) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchSetLocation(itemID, {
-        data: {
-          location: newLocation
-        },
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          ossData.partialUpdate({ location: newLocation });
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [itemID, ossData, library]
-  );
-
-  const setEditors = useCallback(
-    (newEditors: UserID[], callback?: () => void) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchSetEditors(itemID, {
-        data: {
-          users: newEditors
-        },
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          ossData.partialUpdate({ editors: newEditors });
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [itemID, ossData, library]
-  );
-
-  const savePositions = useCallback(
-    (data: IPositionsData, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchUpdatePositions(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          library.localUpdateTimestamp(Number(itemID));
-          callback?.();
-        }
-      });
-    },
-    [itemID, library]
-  );
-
-  const createOperation = useCallback(
-    (data: IOperationCreateData, callback?: DataCallback<IOperationData>) => {
-      setProcessingError(undefined);
-      postCreateOperation(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          ossData.setData(newData.oss);
-          library.localUpdateTimestamp(newData.oss.id);
-          callback?.(newData.new_operation);
-        }
-      });
-    },
-    [itemID, library, ossData]
-  );
-
-  const deleteOperation = useCallback(
-    (data: IOperationDeleteData, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchDeleteOperation(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          ossData.setData(newData);
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [itemID, library, ossData]
-  );
-
-  const createInput = useCallback(
-    (data: ITargetOperation, callback?: DataCallback<ILibraryItem>) => {
-      setProcessingError(undefined);
-      patchCreateInput(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          ossData.setData(newData.oss);
-          library.reloadItems(() => {
-            callback?.(newData.new_schema);
-          });
-        }
-      });
-    },
-    [itemID, library, ossData]
-  );
-
-  const setInput = useCallback(
-    (data: IOperationSetInputData, callback?: () => void) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchSetInput(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          ossData.setData(newData);
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [itemID, ossData, library]
-  );
-
-  const updateOperation = useCallback(
-    (data: IOperationUpdateData, callback?: () => void) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchUpdateOperation(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          ossData.setData(newData);
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [itemID, library, ossData]
-  );
-
-  const executeOperation = useCallback(
-    (data: ITargetOperation, callback?: () => void) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      postExecuteOperation(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          ossData.setData(newData);
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [itemID, library, ossData]
-  );
-
-  const relocateConstituents = useCallback(
-    (data: ICstRelocateData, callback?: () => void) => {
-      if (!ossData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      postRelocateConstituents({
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          ossData.reload();
-          library.reloadItems(callback);
-        }
-      });
-    },
-    [library, ossData]
-  );
-
-  return (
-    <OssContext
-      value={{
-        schema: ossData.schema,
-        itemID,
-        loading: ossData.loading,
-        loadingError: ossData.loadingError,
-        processing,
-        processingError,
-        isOwned,
-        update,
-
-        setOwner,
-        setEditors,
-        setAccessPolicy,
-        setLocation,
-
-        savePositions,
-        createOperation,
-        deleteOperation,
-        createInput,
-        setInput,
-        updateOperation,
-        executeOperation,
-        relocateConstituents
-      }}
-    >
-      {children}
-    </OssContext>
-  );
-};
diff --git a/rsconcept/frontend/src/context/RSFormContext.tsx b/rsconcept/frontend/src/context/RSFormContext.tsx
deleted file mode 100644
index 5148c11c..00000000
--- a/rsconcept/frontend/src/context/RSFormContext.tsx
+++ /dev/null
@@ -1,592 +0,0 @@
-'use client';
-
-import { createContext, useCallback, useContext, useMemo, useState } from 'react';
-
-import { DataCallback } from '@/backend/apiTransport';
-import { useAuth } from '@/backend/auth/useAuth';
-import {
-  patchLibraryItem,
-  patchSetAccessPolicy,
-  patchSetEditors,
-  patchSetLocation,
-  patchSetOwner,
-  postCreateVersion
-} from '@/backend/library';
-import { postFindPredecessor } from '@/backend/oss';
-import {
-  getTRSFile,
-  patchDeleteConstituenta,
-  patchInlineSynthesis,
-  patchMoveConstituenta,
-  patchProduceStructure,
-  patchRenameConstituenta,
-  patchResetAliases,
-  patchRestoreOrder,
-  patchSubstituteConstituents,
-  patchUpdateConstituenta,
-  patchUploadTRS,
-  postCreateConstituenta
-} from '@/backend/rsforms';
-import { deleteVersion, patchRestoreVersion, patchVersion } from '@/backend/versions';
-import { type ErrorData } from '@/components/info/InfoError';
-import useRSFormDetails from '@/hooks/useRSFormDetails';
-import { AccessPolicy, ILibraryItem, IVersionData, VersionID } from '@/models/library';
-import { ILibraryUpdateData } from '@/models/library';
-import { ICstSubstituteData } from '@/models/oss';
-import {
-  ConstituentaID,
-  IConstituentaList,
-  IConstituentaMeta,
-  IConstituentaReference,
-  ICstCreateData,
-  ICstMovetoData,
-  ICstRenameData,
-  ICstUpdateData,
-  IInlineSynthesisData,
-  IRSForm,
-  IRSFormData,
-  IRSFormUploadData,
-  ITargetCst
-} from '@/models/rsform';
-import { UserID } from '@/models/user';
-import { contextOutsideScope } from '@/utils/labels';
-
-import { useGlobalOss } from './GlobalOssContext';
-import { useLibrary } from './LibraryContext';
-
-interface IRSFormContext {
-  schema?: IRSForm;
-  itemID: string;
-  versionID?: string;
-
-  loading: boolean;
-  errorLoading: ErrorData;
-  processing: boolean;
-  processingError: ErrorData;
-
-  isArchive: boolean;
-  isOwned: boolean;
-
-  update: (data: ILibraryUpdateData, callback?: DataCallback<ILibraryItem>) => void;
-  download: (callback: DataCallback<Blob>) => void;
-  upload: (data: IRSFormUploadData, callback: () => void) => void;
-
-  setOwner: (newOwner: UserID, callback?: () => void) => void;
-  setAccessPolicy: (newPolicy: AccessPolicy, callback?: () => void) => void;
-  setLocation: (newLocation: string, callback?: () => void) => void;
-  setEditors: (newEditors: UserID[], callback?: () => void) => void;
-
-  resetAliases: (callback: () => void) => void;
-  restoreOrder: (callback: () => void) => void;
-  produceStructure: (data: ITargetCst, callback?: DataCallback<ConstituentaID[]>) => void;
-  inlineSynthesis: (data: IInlineSynthesisData, callback?: DataCallback<IRSFormData>) => void;
-
-  cstCreate: (data: ICstCreateData, callback?: DataCallback<IConstituentaMeta>) => void;
-  cstRename: (data: ICstRenameData, callback?: DataCallback<IConstituentaMeta>) => void;
-  cstSubstitute: (data: ICstSubstituteData, callback?: () => void) => void;
-  cstUpdate: (data: ICstUpdateData, callback?: DataCallback<IConstituentaMeta>) => void;
-  cstDelete: (data: IConstituentaList, callback?: () => void) => void;
-  cstMoveTo: (data: ICstMovetoData, callback?: () => void) => void;
-  findPredecessor: (data: ITargetCst, callback: (reference: IConstituentaReference) => void) => void;
-
-  versionCreate: (data: IVersionData, callback?: (version: VersionID) => void) => void;
-  versionUpdate: (target: VersionID, data: IVersionData, callback?: () => void) => void;
-  versionDelete: (target: VersionID, callback?: () => void) => void;
-  versionRestore: (target: string, callback?: () => void) => void;
-}
-
-const RSFormContext = createContext<IRSFormContext | null>(null);
-export const useRSForm = () => {
-  const context = useContext(RSFormContext);
-  if (context === null) {
-    throw new Error(contextOutsideScope('useRSForm', 'RSFormState'));
-  }
-  return context;
-};
-
-interface RSFormStateProps {
-  itemID: string;
-  versionID?: string;
-}
-
-export const RSFormState = ({ itemID, versionID, children }: React.PropsWithChildren<RSFormStateProps>) => {
-  const library = useLibrary();
-  const oss = useGlobalOss();
-  const { user } = useAuth();
-  const rsData = useRSFormDetails({ target: itemID, version: versionID });
-  const [processing, setProcessing] = useState(false);
-  const [processingError, setProcessingError] = useState<ErrorData>(undefined);
-
-  const isOwned = useMemo(() => {
-    return user?.id === rsData.schema?.owner || false;
-  }, [user, rsData.schema?.owner]);
-
-  const isArchive = useMemo(() => !!versionID, [versionID]);
-
-  const update = useCallback(
-    (data: ILibraryUpdateData, callback?: DataCallback<ILibraryItem>) => {
-      if (!rsData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchLibraryItem(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(Object.assign(rsData.schema!, newData));
-          library.localUpdateItem(newData);
-          oss.invalidateItem(newData.id);
-          callback?.(newData);
-        }
-      });
-    },
-    [itemID, rsData, library, oss]
-  );
-
-  const upload = useCallback(
-    (data: IRSFormUploadData, callback?: () => void) => {
-      if (!rsData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchUploadTRS(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData);
-          library.localUpdateItem(newData);
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData, library]
-  );
-
-  const setOwner = useCallback(
-    (newOwner: UserID, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchSetOwner(itemID, {
-        data: {
-          user: newOwner
-        },
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          rsData.partialUpdate({ owner: newOwner });
-          library.localUpdateItem({ id: Number(itemID), owner: newOwner });
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData, library]
-  );
-
-  const setAccessPolicy = useCallback(
-    (newPolicy: AccessPolicy, callback?: () => void) => {
-      if (!rsData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchSetAccessPolicy(itemID, {
-        data: {
-          access_policy: newPolicy
-        },
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          rsData.partialUpdate({ access_policy: newPolicy });
-          library.localUpdateItem({ id: Number(itemID), access_policy: newPolicy });
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData, library]
-  );
-
-  const setLocation = useCallback(
-    (newLocation: string, callback?: () => void) => {
-      if (!rsData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchSetLocation(itemID, {
-        data: {
-          location: newLocation
-        },
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          rsData.partialUpdate({ location: newLocation });
-          library.localUpdateItem({ id: Number(itemID), location: newLocation });
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData, library]
-  );
-
-  const setEditors = useCallback(
-    (newEditors: UserID[], callback?: () => void) => {
-      if (!rsData.schema) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchSetEditors(itemID, {
-        data: {
-          users: newEditors
-        },
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          rsData.partialUpdate({ editors: newEditors });
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData]
-  );
-
-  const resetAliases = useCallback(
-    (callback?: () => void) => {
-      if (!rsData.schema || !user) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchResetAliases(itemID, {
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData);
-          library.localUpdateTimestamp(newData.id);
-          oss.invalidateItem(newData.id);
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData, user, library, oss]
-  );
-
-  const restoreOrder = useCallback(
-    (callback?: () => void) => {
-      if (!rsData.schema || !user) {
-        return;
-      }
-      setProcessingError(undefined);
-      patchRestoreOrder(itemID, {
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData);
-          library.localUpdateTimestamp(newData.id);
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData, user, library]
-  );
-
-  const produceStructure = useCallback(
-    (data: ITargetCst, callback?: DataCallback<ConstituentaID[]>) => {
-      setProcessingError(undefined);
-      patchProduceStructure(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData.schema);
-          library.localUpdateTimestamp(newData.schema.id);
-          oss.invalidateItem(newData.schema.id);
-          callback?.(newData.cst_list);
-        }
-      });
-    },
-    [rsData, itemID, library, oss]
-  );
-
-  const download = useCallback(
-    (callback: DataCallback<Blob>) => {
-      setProcessingError(undefined);
-      getTRSFile(itemID, String(rsData.schema?.version ?? ''), {
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: callback
-      });
-    },
-    [itemID, rsData]
-  );
-
-  const cstCreate = useCallback(
-    (data: ICstCreateData, callback?: DataCallback<IConstituentaMeta>) => {
-      setProcessingError(undefined);
-      postCreateConstituenta(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData.schema);
-          library.localUpdateTimestamp(newData.schema.id);
-          oss.invalidateItem(newData.schema.id);
-          callback?.(newData.new_cst);
-        }
-      });
-    },
-    [itemID, rsData, library, oss]
-  );
-
-  const cstDelete = useCallback(
-    (data: IConstituentaList, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchDeleteConstituenta(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData);
-          library.localUpdateTimestamp(newData.id);
-          oss.invalidateItem(newData.id);
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData, library, oss]
-  );
-
-  const cstUpdate = useCallback(
-    (data: ICstUpdateData, callback?: DataCallback<IConstituentaMeta>) => {
-      setProcessingError(undefined);
-      patchUpdateConstituenta(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData =>
-          rsData.reload(setProcessing, () => {
-            library.localUpdateTimestamp(Number(itemID));
-            oss.invalidateItem(Number(itemID));
-            callback?.(newData);
-          })
-      });
-    },
-    [itemID, rsData, library, oss]
-  );
-
-  const cstRename = useCallback(
-    (data: ICstRenameData, callback?: DataCallback<IConstituentaMeta>) => {
-      setProcessingError(undefined);
-      patchRenameConstituenta(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData.schema);
-          library.localUpdateTimestamp(newData.schema.id);
-          oss.invalidateItem(newData.schema.id);
-          callback?.(newData.new_cst);
-        }
-      });
-    },
-    [rsData, itemID, library, oss]
-  );
-
-  const cstSubstitute = useCallback(
-    (data: ICstSubstituteData, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchSubstituteConstituents(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData);
-          library.localUpdateTimestamp(newData.id);
-          oss.invalidateItem(newData.id);
-          callback?.();
-        }
-      });
-    },
-    [rsData, itemID, library, oss]
-  );
-
-  const cstMoveTo = useCallback(
-    (data: ICstMovetoData, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchMoveConstituenta(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData);
-          library.localUpdateTimestamp(Number(itemID));
-          callback?.();
-        }
-      });
-    },
-    [itemID, rsData, library]
-  );
-
-  const versionCreate = useCallback(
-    (data: IVersionData, callback?: (version: number) => void) => {
-      setProcessingError(undefined);
-      postCreateVersion(itemID, {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData.schema);
-          library.localUpdateTimestamp(Number(itemID));
-          callback?.(newData.version);
-        }
-      });
-    },
-    [itemID, rsData, library]
-  );
-
-  const findPredecessor = useCallback((data: ITargetCst, callback: (reference: IConstituentaReference) => void) => {
-    setProcessingError(undefined);
-    postFindPredecessor({
-      data: data,
-      showError: true,
-      setLoading: setProcessing,
-      onError: setProcessingError,
-      onSuccess: callback
-    });
-  }, []);
-
-  const versionUpdate = useCallback(
-    (target: number, data: IVersionData, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchVersion(String(target), {
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          const newVersions = rsData.schema!.versions.map(prev => {
-            if (prev.id === target) {
-              prev.description = data.description;
-              prev.version = data.version;
-              return prev;
-            } else {
-              return prev;
-            }
-          });
-          rsData.partialUpdate({ versions: newVersions });
-          callback?.();
-        }
-      });
-    },
-    [rsData]
-  );
-
-  const versionDelete = useCallback(
-    (target: number, callback?: () => void) => {
-      setProcessingError(undefined);
-      deleteVersion(String(target), {
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: () => {
-          const newVersions = rsData.schema!.versions.filter(prev => prev.id !== target);
-          rsData.partialUpdate({ versions: newVersions });
-          callback?.();
-        }
-      });
-    },
-    [rsData]
-  );
-
-  const versionRestore = useCallback(
-    (target: string, callback?: () => void) => {
-      setProcessingError(undefined);
-      patchRestoreVersion(target, {
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData);
-          library.localUpdateItem(newData);
-          callback?.();
-        }
-      });
-    },
-    [rsData, library]
-  );
-
-  const inlineSynthesis = useCallback(
-    (data: IInlineSynthesisData, callback?: DataCallback<IRSFormData>) => {
-      setProcessingError(undefined);
-      patchInlineSynthesis({
-        data: data,
-        showError: true,
-        setLoading: setProcessing,
-        onError: setProcessingError,
-        onSuccess: newData => {
-          rsData.setSchema(newData);
-          library.localUpdateTimestamp(newData.id);
-          oss.invalidateItem(newData.id);
-          callback?.(newData);
-        }
-      });
-    },
-    [rsData, library, oss]
-  );
-
-  return (
-    <RSFormContext
-      value={{
-        schema: rsData.schema,
-        itemID,
-        versionID,
-        loading: rsData.loading,
-        errorLoading: rsData.error,
-        processing,
-        processingError,
-        isOwned,
-        isArchive,
-        update,
-        download,
-        upload,
-        restoreOrder,
-        resetAliases,
-        produceStructure,
-        inlineSynthesis,
-        setOwner,
-        setEditors,
-        setAccessPolicy,
-        setLocation,
-
-        cstUpdate,
-        cstCreate,
-        cstRename,
-        cstSubstitute,
-        cstDelete,
-        cstMoveTo,
-        findPredecessor,
-
-        versionCreate,
-        versionUpdate,
-        versionDelete,
-        versionRestore
-      }}
-    >
-      {children}
-    </RSFormContext>
-  );
-};
diff --git a/rsconcept/frontend/src/dialogs/DlgChangeInputSchema.tsx b/rsconcept/frontend/src/dialogs/DlgChangeInputSchema.tsx
index a7790564..8c0bbaac 100644
--- a/rsconcept/frontend/src/dialogs/DlgChangeInputSchema.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgChangeInputSchema.tsx
@@ -3,12 +3,12 @@
 import clsx from 'clsx';
 import { useState } from 'react';
 
+import { useLibrary } from '@/backend/library/useLibrary';
 import { IconReset } from '@/components/Icons';
 import PickSchema from '@/components/select/PickSchema';
 import Label from '@/components/ui/Label';
 import MiniButton from '@/components/ui/MiniButton';
 import Modal from '@/components/ui/Modal';
-import { useLibrary } from '@/context/LibraryContext';
 import { ILibraryItem, LibraryItemID, LibraryItemType } from '@/models/library';
 import { IOperation, IOperationSchema, OperationID } from '@/models/oss';
 import { sortItemsForOSS } from '@/models/ossAPI';
@@ -23,8 +23,8 @@ export interface DlgChangeInputSchemaProps {
 function DlgChangeInputSchema() {
   const { oss, target, onSubmit } = useDialogsStore(state => state.props as DlgChangeInputSchemaProps);
   const [selected, setSelected] = useState<LibraryItemID | undefined>(target.result ?? undefined);
-  const library = useLibrary();
-  const sortedItems = sortItemsForOSS(oss, library.items);
+  const { items } = useLibrary();
+  const sortedItems = sortItemsForOSS(oss, items);
   const isValid = target.result !== selected;
 
   function baseFilter(item: ILibraryItem) {
diff --git a/rsconcept/frontend/src/dialogs/DlgCloneLibraryItem.tsx b/rsconcept/frontend/src/dialogs/DlgCloneLibraryItem.tsx
index c8107adf..cb9ae85d 100644
--- a/rsconcept/frontend/src/dialogs/DlgCloneLibraryItem.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCloneLibraryItem.tsx
@@ -6,6 +6,8 @@ import { toast } from 'react-toastify';
 
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
+import { IRSFormCloneDTO } from '@/backend/library/api';
+import { useCloneItem } from '@/backend/library/useCloneItem';
 import { VisibilityIcon } from '@/components/DomainIcons';
 import SelectAccessPolicy from '@/components/select/SelectAccessPolicy';
 import SelectLocationContext from '@/components/select/SelectLocationContext';
@@ -16,11 +18,10 @@ import MiniButton from '@/components/ui/MiniButton';
 import Modal from '@/components/ui/Modal';
 import TextArea from '@/components/ui/TextArea';
 import TextInput from '@/components/ui/TextInput';
-import { useLibrary } from '@/context/LibraryContext';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { AccessPolicy, ILibraryItem, LocationHead } from '@/models/library';
 import { cloneTitle, combineLocation, validateLocation } from '@/models/libraryAPI';
-import { ConstituentaID, IRSFormCloneData } from '@/models/rsform';
+import { ConstituentaID } from '@/models/rsform';
 import { useDialogsStore } from '@/stores/dialogs';
 import { information } from '@/utils/labels';
 
@@ -50,7 +51,7 @@ function DlgCloneLibraryItem() {
   const [body, setBody] = useState(initialLocation.substring(3));
   const location = combineLocation(head, body);
 
-  const { cloneItem, folders } = useLibrary();
+  const { cloneItem } = useCloneItem();
 
   const canSubmit = title !== '' && alias !== '' && validateLocation(location);
 
@@ -60,7 +61,8 @@ function DlgCloneLibraryItem() {
   }
 
   function handleSubmit() {
-    const data: IRSFormCloneData = {
+    const data: IRSFormCloneDTO = {
+      id: base.id,
       item_type: base.item_type,
       title: title,
       alias: alias,
@@ -73,7 +75,7 @@ function DlgCloneLibraryItem() {
     if (onlySelected) {
       data.items = selected;
     }
-    cloneItem(base.id, data, newSchema => {
+    cloneItem(data, newSchema => {
       toast.success(information.cloneComplete(newSchema.alias));
       router.push(urls.schema(newSchema.id));
     });
@@ -128,7 +130,7 @@ function DlgCloneLibraryItem() {
             excluded={!user?.is_staff ? [LocationHead.LIBRARY] : []}
           />
         </div>
-        <SelectLocationContext folderTree={folders} value={location} onChange={handleSelectLocation} />
+        <SelectLocationContext value={location} onChange={handleSelectLocation} />
         <TextArea
           id='dlg_cst_body'
           label='Путь'
diff --git a/rsconcept/frontend/src/dialogs/DlgCreateCst/DlgCreateCst.tsx b/rsconcept/frontend/src/dialogs/DlgCreateCst/DlgCreateCst.tsx
index a8fe7f91..39c311e2 100644
--- a/rsconcept/frontend/src/dialogs/DlgCreateCst/DlgCreateCst.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCreateCst/DlgCreateCst.tsx
@@ -2,18 +2,19 @@
 
 import { useState } from 'react';
 
+import { ICstCreateDTO } from '@/backend/rsform/api';
 import Modal from '@/components/ui/Modal';
 import usePartialUpdate from '@/hooks/usePartialUpdate';
-import { CstType, ICstCreateData, IRSForm } from '@/models/rsform';
+import { CstType, IRSForm } from '@/models/rsform';
 import { generateAlias } from '@/models/rsformAPI';
 import { useDialogsStore } from '@/stores/dialogs';
 
 import FormCreateCst from './FormCreateCst';
 
 export interface DlgCreateCstProps {
-  initial?: ICstCreateData;
+  initial?: ICstCreateDTO;
   schema: IRSForm;
-  onCreate: (data: ICstCreateData) => void;
+  onCreate: (data: ICstCreateDTO) => void;
 }
 
 function DlgCreateCst() {
diff --git a/rsconcept/frontend/src/dialogs/DlgCreateCst/FormCreateCst.tsx b/rsconcept/frontend/src/dialogs/DlgCreateCst/FormCreateCst.tsx
index 42301bc5..29124f05 100644
--- a/rsconcept/frontend/src/dialogs/DlgCreateCst/FormCreateCst.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCreateCst/FormCreateCst.tsx
@@ -3,13 +3,14 @@
 import clsx from 'clsx';
 import { useEffect, useState } from 'react';
 
+import { ICstCreateDTO } from '@/backend/rsform/api';
 import BadgeHelp from '@/components/info/BadgeHelp';
 import RSInput from '@/components/RSInput';
 import SelectSingle from '@/components/ui/SelectSingle';
 import TextArea from '@/components/ui/TextArea';
 import TextInput from '@/components/ui/TextInput';
 import { HelpTopic } from '@/models/miscellaneous';
-import { CstType, ICstCreateData, IRSForm } from '@/models/rsform';
+import { CstType, IRSForm } from '@/models/rsform';
 import { generateAlias, isBaseSet, isBasicConcept, isFunctional, validateNewAlias } from '@/models/rsformAPI';
 import { PARAMETER } from '@/utils/constants';
 import { labelCstType } from '@/utils/labels';
@@ -17,9 +18,9 @@ import { SelectorCstType } from '@/utils/selectors';
 
 interface FormCreateCstProps {
   schema: IRSForm;
-  state: ICstCreateData;
+  state: ICstCreateDTO;
 
-  partialUpdate: React.Dispatch<Partial<ICstCreateData>>;
+  partialUpdate: React.Dispatch<Partial<ICstCreateDTO>>;
   setValidated?: React.Dispatch<React.SetStateAction<boolean>>;
 }
 
diff --git a/rsconcept/frontend/src/dialogs/DlgCreateOperation/DlgCreateOperation.tsx b/rsconcept/frontend/src/dialogs/DlgCreateOperation/DlgCreateOperation.tsx
index b8b330cf..6edf77ee 100644
--- a/rsconcept/frontend/src/dialogs/DlgCreateOperation/DlgCreateOperation.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCreateOperation/DlgCreateOperation.tsx
@@ -4,12 +4,13 @@ import clsx from 'clsx';
 import { useEffect, useState } from 'react';
 import { TabList, TabPanel, Tabs } from 'react-tabs';
 
+import { useLibrary } from '@/backend/library/useLibrary';
+import { IOperationCreateDTO } from '@/backend/oss/api';
 import Modal from '@/components/ui/Modal';
 import TabLabel from '@/components/ui/TabLabel';
-import { useLibrary } from '@/context/LibraryContext';
 import { LibraryItemID } from '@/models/library';
 import { HelpTopic } from '@/models/miscellaneous';
-import { IOperationCreateData, IOperationSchema, OperationID, OperationType } from '@/models/oss';
+import { IOperationSchema, OperationID, OperationType } from '@/models/oss';
 import { useDialogsStore } from '@/stores/dialogs';
 import { describeOperationType, labelOperationType } from '@/utils/labels';
 
@@ -18,7 +19,7 @@ import TabSynthesisOperation from './TabSynthesisOperation';
 
 export interface DlgCreateOperationProps {
   oss: IOperationSchema;
-  onCreate: (data: IOperationCreateData) => void;
+  onCreate: (data: IOperationCreateDTO) => void;
   initialInputs: OperationID[];
 }
 
@@ -28,8 +29,9 @@ export enum TabID {
 }
 
 function DlgCreateOperation() {
+  const { items: libraryItems } = useLibrary();
+
   const { oss, onCreate, initialInputs } = useDialogsStore(state => state.props as DlgCreateOperationProps);
-  const library = useLibrary();
   const [activeTab, setActiveTab] = useState(initialInputs.length > 0 ? TabID.SYNTHESIS : TabID.INPUT);
 
   const [alias, setAlias] = useState('');
@@ -56,17 +58,17 @@ function DlgCreateOperation() {
 
   useEffect(() => {
     if (attachedID) {
-      const schema = library.items.find(value => value.id === attachedID);
+      const schema = libraryItems.find(value => value.id === attachedID);
       if (schema) {
         setAlias(schema.alias);
         setTitle(schema.title);
         setComment(schema.comment);
       }
     }
-  }, [attachedID, library]);
+  }, [attachedID, libraryItems]);
 
   const handleSubmit = () => {
-    const data: IOperationCreateData = {
+    onCreate({
       item_data: {
         position_x: 0,
         position_y: 0,
@@ -79,8 +81,7 @@ function DlgCreateOperation() {
       positions: [],
       arguments: activeTab === TabID.INPUT ? undefined : inputs.length > 0 ? inputs : undefined,
       create_schema: createSchema
-    };
-    onCreate(data);
+    });
   };
 
   function handleSelectTab(newTab: TabID, last: TabID) {
diff --git a/rsconcept/frontend/src/dialogs/DlgCreateOperation/TabInputOperation.tsx b/rsconcept/frontend/src/dialogs/DlgCreateOperation/TabInputOperation.tsx
index 39042c64..3cdb9d35 100644
--- a/rsconcept/frontend/src/dialogs/DlgCreateOperation/TabInputOperation.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCreateOperation/TabInputOperation.tsx
@@ -2,6 +2,7 @@
 
 import { useEffect } from 'react';
 
+import { useLibrary } from '@/backend/library/useLibrary';
 import { IconReset } from '@/components/Icons';
 import PickSchema from '@/components/select/PickSchema';
 import Checkbox from '@/components/ui/Checkbox';
@@ -9,7 +10,6 @@ import Label from '@/components/ui/Label';
 import MiniButton from '@/components/ui/MiniButton';
 import TextArea from '@/components/ui/TextArea';
 import TextInput from '@/components/ui/TextInput';
-import { useLibrary } from '@/context/LibraryContext';
 import { ILibraryItem, LibraryItemID, LibraryItemType } from '@/models/library';
 import { IOperationSchema } from '@/models/oss';
 import { sortItemsForOSS } from '@/models/ossAPI';
@@ -41,8 +41,8 @@ function TabInputOperation({
   createSchema,
   onChangeCreateSchema
 }: TabInputOperationProps) {
-  const library = useLibrary();
-  const sortedItems = sortItemsForOSS(oss, library.items);
+  const { items: libraryItems } = useLibrary();
+  const sortedItems = sortItemsForOSS(oss, libraryItems);
 
   function baseFilter(item: ILibraryItem) {
     return !oss.schemas.includes(item.id);
diff --git a/rsconcept/frontend/src/dialogs/DlgCreateVersion.tsx b/rsconcept/frontend/src/dialogs/DlgCreateVersion.tsx
index 68191af5..d4dc8abf 100644
--- a/rsconcept/frontend/src/dialogs/DlgCreateVersion.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCreateVersion.tsx
@@ -3,18 +3,19 @@
 import clsx from 'clsx';
 import { useState } from 'react';
 
+import { IVersionCreateDTO } from '@/backend/library/api';
 import Checkbox from '@/components/ui/Checkbox';
 import Modal from '@/components/ui/Modal';
 import TextArea from '@/components/ui/TextArea';
 import TextInput from '@/components/ui/TextInput';
-import { IVersionCreateData, IVersionInfo } from '@/models/library';
+import { IVersionInfo } from '@/models/library';
 import { nextVersion } from '@/models/libraryAPI';
 import { ConstituentaID } from '@/models/rsform';
 import { useDialogsStore } from '@/stores/dialogs';
 
 export interface DlgCreateVersionProps {
   versions: IVersionInfo[];
-  onCreate: (data: IVersionCreateData) => void;
+  onCreate: (data: IVersionCreateDTO) => void;
   selected: ConstituentaID[];
   totalCount: number;
 }
@@ -28,14 +29,11 @@ function DlgCreateVersion() {
   const canSubmit = !versions.find(ver => ver.version === version);
 
   function handleSubmit() {
-    const data: IVersionCreateData = {
+    onCreate({
       version: version,
-      description: description
-    };
-    if (onlySelected) {
-      data.items = selected;
-    }
-    onCreate(data);
+      description: description,
+      items: onlySelected ? selected : undefined
+    });
   }
 
   return (
diff --git a/rsconcept/frontend/src/dialogs/DlgCstTemplate/DlgCstTemplate.tsx b/rsconcept/frontend/src/dialogs/DlgCstTemplate/DlgCstTemplate.tsx
index 482bff28..331c49ac 100644
--- a/rsconcept/frontend/src/dialogs/DlgCstTemplate/DlgCstTemplate.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCstTemplate/DlgCstTemplate.tsx
@@ -1,15 +1,17 @@
 'use client';
 
 import clsx from 'clsx';
-import { useEffect, useState } from 'react';
+import { Suspense, useEffect, useState } from 'react';
 import { TabList, TabPanel, Tabs } from 'react-tabs';
 
+import { ICstCreateDTO } from '@/backend/rsform/api';
+import { useRSForm } from '@/backend/rsform/useRSForm';
+import Loader from '@/components/ui/Loader';
 import Modal from '@/components/ui/Modal';
 import TabLabel from '@/components/ui/TabLabel';
-import { useLibrary } from '@/context/LibraryContext';
 import usePartialUpdate from '@/hooks/usePartialUpdate';
 import { HelpTopic } from '@/models/miscellaneous';
-import { CstType, ICstCreateData, IRSForm } from '@/models/rsform';
+import { CstType, IRSForm } from '@/models/rsform';
 import { generateAlias, validateNewAlias } from '@/models/rsformAPI';
 import { inferTemplatedType, substituteTemplateArgs } from '@/models/rslangAPI';
 import { useDialogsStore } from '@/stores/dialogs';
@@ -21,7 +23,7 @@ import TabTemplate, { ITemplateState } from './TabTemplate';
 
 export interface DlgCstTemplateProps {
   schema: IRSForm;
-  onCreate: (data: ICstCreateData) => void;
+  onCreate: (data: ICstCreateDTO) => void;
   insertAfter?: number;
 }
 
@@ -33,16 +35,15 @@ export enum TabID {
 
 function DlgCstTemplate() {
   const { schema, onCreate, insertAfter } = useDialogsStore(state => state.props as DlgCstTemplateProps);
-  const { retrieveTemplate } = useLibrary();
   const [activeTab, setActiveTab] = useState(TabID.TEMPLATE);
 
-  const [templateSchema, setTemplateSchema] = useState<IRSForm | undefined>(undefined);
   const [template, updateTemplate] = usePartialUpdate<ITemplateState>({});
+  const { schema: templateSchema } = useRSForm({ itemID: template.templateID });
   const [substitutes, updateSubstitutes] = usePartialUpdate<IArgumentsState>({
     definition: '',
     arguments: []
   });
-  const [constituenta, updateConstituenta] = usePartialUpdate<ICstCreateData>({
+  const [constituenta, updateConstituenta] = usePartialUpdate<ICstCreateDTO>({
     cst_type: CstType.TERM,
     insert_after: insertAfter ?? null,
     alias: generateAlias(CstType.TERM, schema),
@@ -67,14 +68,6 @@ function DlgCstTemplate() {
     return true;
   }
 
-  useEffect(() => {
-    if (!template.templateID) {
-      setTemplateSchema(undefined);
-    } else {
-      retrieveTemplate(template.templateID, setTemplateSchema);
-    }
-  }, [template.templateID, retrieveTemplate]);
-
   useEffect(() => {
     if (!template.prototype) {
       updateConstituenta({
@@ -148,7 +141,9 @@ function DlgCstTemplate() {
         </TabList>
 
         <TabPanel>
-          <TabTemplate state={template} partialUpdate={updateTemplate} templateSchema={templateSchema} />
+          <Suspense fallback={<Loader />}>
+            <TabTemplate state={template} partialUpdate={updateTemplate} templateSchema={templateSchema} />
+          </Suspense>
         </TabPanel>
 
         <TabPanel>
diff --git a/rsconcept/frontend/src/dialogs/DlgCstTemplate/TabArguments.tsx b/rsconcept/frontend/src/dialogs/DlgCstTemplate/TabArguments.tsx
index 0ece94c6..95e8f32d 100644
--- a/rsconcept/frontend/src/dialogs/DlgCstTemplate/TabArguments.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCstTemplate/TabArguments.tsx
@@ -92,7 +92,7 @@ function TabArguments({ state, schema, partialUpdate }: TabArgumentsProps) {
       cell: props => (
         <div
           className={clsx(
-            'min-w-[9.3rem] max-w-[9.3rem]', // prettier: split lines
+            'min-w-[9.3rem] max-w-[9.3rem]', //
             'text-sm break-words'
           )}
         >
@@ -133,7 +133,7 @@ function TabArguments({ state, schema, partialUpdate }: TabArgumentsProps) {
         noFooter
         noHeader
         className={clsx(
-          'max-h-[5.8rem] min-h-[5.8rem]', // prettier: split lines
+          'max-h-[5.8rem] min-h-[5.8rem]', //
           'cc-scroll-y',
           'text-sm',
           'border',
@@ -148,7 +148,7 @@ function TabArguments({ state, schema, partialUpdate }: TabArgumentsProps) {
 
       <div
         className={clsx(
-          'my-4', // prettier: split lines
+          'my-4', //
           'flex gap-2 justify-center items-center',
           'select-none'
         )}
diff --git a/rsconcept/frontend/src/dialogs/DlgCstTemplate/TabTemplate.tsx b/rsconcept/frontend/src/dialogs/DlgCstTemplate/TabTemplate.tsx
index 874f0d7d..175e58a0 100644
--- a/rsconcept/frontend/src/dialogs/DlgCstTemplate/TabTemplate.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgCstTemplate/TabTemplate.tsx
@@ -2,11 +2,11 @@
 
 import { Dispatch, useEffect, useState } from 'react';
 
+import { useTemplatesSuspense } from '@/backend/library/useTemplates';
 import RSInput from '@/components/RSInput';
 import PickConstituenta from '@/components/select/PickConstituenta';
 import SelectSingle from '@/components/ui/SelectSingle';
 import TextArea from '@/components/ui/TextArea';
-import { useLibrary } from '@/context/LibraryContext';
 import { CATEGORY_CST_TYPE, IConstituenta, IRSForm } from '@/models/rsform';
 import { applyFilterCategory } from '@/models/rsformAPI';
 import { prefixes } from '@/utils/constants';
@@ -24,7 +24,7 @@ interface TabTemplateProps {
 }
 
 function TabTemplate({ state, partialUpdate, templateSchema }: TabTemplateProps) {
-  const { templates } = useLibrary();
+  const { templates } = useTemplatesSuspense();
 
   const [filteredData, setFilteredData] = useState<IConstituenta[]>([]);
 
diff --git a/rsconcept/frontend/src/dialogs/DlgEditOperation/DlgEditOperation.tsx b/rsconcept/frontend/src/dialogs/DlgEditOperation/DlgEditOperation.tsx
index 3356c3d9..8fb5a871 100644
--- a/rsconcept/frontend/src/dialogs/DlgEditOperation/DlgEditOperation.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgEditOperation/DlgEditOperation.tsx
@@ -4,19 +4,13 @@ import clsx from 'clsx';
 import { useCallback, useEffect, useState } from 'react';
 import { TabList, TabPanel, Tabs } from 'react-tabs';
 
+import { IOperationUpdateDTO } from '@/backend/oss/api';
+import { useRSForms } from '@/backend/rsform/useRSForms';
 import Modal from '@/components/ui/Modal';
 import TabLabel from '@/components/ui/TabLabel';
-import useRSFormCache from '@/hooks/useRSFormCache';
 import { LibraryItemID } from '@/models/library';
 import { HelpTopic } from '@/models/miscellaneous';
-import {
-  ICstSubstitute,
-  IOperation,
-  IOperationSchema,
-  IOperationUpdateData,
-  OperationID,
-  OperationType
-} from '@/models/oss';
+import { ICstSubstitute, IOperation, IOperationSchema, OperationID, OperationType } from '@/models/oss';
 import { SubstitutionValidator } from '@/models/ossAPI';
 import { ConstituentaID } from '@/models/rsform';
 import { useDialogsStore } from '@/stores/dialogs';
@@ -28,7 +22,7 @@ import TabSynthesis from './TabSynthesis';
 export interface DlgEditOperationProps {
   oss: IOperationSchema;
   target: IOperation;
-  onSubmit: (data: IOperationUpdateData) => void;
+  onSubmit: (data: IOperationUpdateDTO) => void;
 }
 
 export enum TabID {
@@ -52,14 +46,11 @@ function DlgEditOperation() {
   const [inputs, setInputs] = useState<OperationID[]>(initialInputs);
   const inputOperations = inputs.map(id => oss.operationByID.get(id)!);
 
-  const [needPreload, setNeedPreload] = useState(false);
-  const [schemasIDs, setSchemaIDs] = useState<LibraryItemID[]>([]);
-
   const [substitutions, setSubstitutions] = useState<ICstSubstitute[]>(target.substitutions);
   const [suggestions, setSuggestions] = useState<ICstSubstitute[]>([]);
 
-  const cache = useRSFormCache();
-  const schemas = schemasIDs.map(id => cache.data.find(item => item.id === id)).filter(item => item !== undefined);
+  const [schemasIDs, setSchemaIDs] = useState<LibraryItemID[]>([]);
+  const schemas = useRSForms(schemasIDs);
 
   const isModified =
     alias !== target.alias ||
@@ -72,7 +63,7 @@ function DlgEditOperation() {
 
   const getSchemaByCst = useCallback(
     (id: ConstituentaID) => {
-      for (const schema of cache.data) {
+      for (const schema of schemas) {
         const cst = schema.items.find(cst => cst.id === id);
         if (cst) {
           return schema;
@@ -80,23 +71,15 @@ function DlgEditOperation() {
       }
       return undefined;
     },
-    [cache.data]
+    [schemas]
   );
 
   useEffect(() => {
-    setNeedPreload(true);
     setSchemaIDs(inputOperations.map(operation => operation.result).filter(id => id !== null));
   }, [inputOperations]);
 
   useEffect(() => {
-    if (needPreload) {
-      setNeedPreload(false);
-      cache.preload(schemasIDs);
-    }
-  }, [schemasIDs, needPreload, cache]);
-
-  useEffect(() => {
-    if (cache.loading || schemas.length !== schemasIDs.length || schemas.length === 0) {
+    if (schemas.length !== schemasIDs.length || schemas.length === 0) {
       return;
     }
     setSubstitutions(prev =>
@@ -112,20 +95,20 @@ function DlgEditOperation() {
         return true;
       })
     );
-  }, [schemasIDs, schemas, cache.loading, getSchemaByCst]);
+  }, [schemasIDs, schemas, getSchemaByCst]);
 
   useEffect(() => {
-    if (cache.loading || schemas.length !== schemasIDs.length || schemas.length === 0) {
+    if (schemas.length !== schemasIDs.length || schemas.length === 0) {
       return;
     }
     const validator = new SubstitutionValidator(schemas, substitutions);
     setIsCorrect(validator.validate());
     setValidationText(validator.msg);
     setSuggestions(validator.suggestions);
-  }, [substitutions, cache.loading, schemas, schemasIDs.length]);
+  }, [substitutions, schemas, schemasIDs.length]);
 
   function handleSubmit() {
-    const data: IOperationUpdateData = {
+    onSubmit({
       target: target.id,
       item_data: {
         alias: alias,
@@ -135,8 +118,7 @@ function DlgEditOperation() {
       positions: [],
       arguments: target.operation_type !== OperationType.SYNTHESIS ? undefined : inputs,
       substitutions: target.operation_type !== OperationType.SYNTHESIS ? undefined : substitutions
-    };
-    onSubmit(data);
+    });
   }
 
   return (
@@ -194,8 +176,6 @@ function DlgEditOperation() {
           <TabPanel>
             <TabSynthesis
               schemas={schemas}
-              loading={cache.loading}
-              error={cache.error}
               validationText={validationText}
               isCorrect={isCorrect}
               substitutions={substitutions}
diff --git a/rsconcept/frontend/src/dialogs/DlgEditOperation/TabSynthesis.tsx b/rsconcept/frontend/src/dialogs/DlgEditOperation/TabSynthesis.tsx
index af6933ee..10998c5a 100644
--- a/rsconcept/frontend/src/dialogs/DlgEditOperation/TabSynthesis.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgEditOperation/TabSynthesis.tsx
@@ -1,15 +1,11 @@
-import { ErrorData } from '@/components/info/InfoError';
 import PickSubstitutions from '@/components/select/PickSubstitutions';
 import TextArea from '@/components/ui/TextArea';
-import DataLoader from '@/components/wrap/DataLoader';
 import { ICstSubstitute } from '@/models/oss';
 import { IRSForm } from '@/models/rsform';
 import { APP_COLORS } from '@/styling/color';
 import { prefixes } from '@/utils/constants';
 
 interface TabSynthesisProps {
-  loading: boolean;
-  error: ErrorData;
   validationText: string;
   isCorrect: boolean;
 
@@ -21,8 +17,6 @@ interface TabSynthesisProps {
 
 function TabSynthesis({
   schemas,
-  loading,
-  error,
   validationText,
   isCorrect,
   substitutions,
@@ -30,24 +24,22 @@ function TabSynthesis({
   suggestions
 }: TabSynthesisProps) {
   return (
-    <DataLoader isLoading={loading} error={error}>
-      <div className='cc-fade-in cc-column mt-3'>
-        <PickSubstitutions
-          schemas={schemas}
-          prefixID={prefixes.dlg_cst_substitutes_list}
-          rows={8}
-          substitutions={substitutions}
-          setSubstitutions={setSubstitutions}
-          suggestions={suggestions}
-        />
-        <TextArea
-          disabled
-          value={validationText}
-          rows={4}
-          style={{ borderColor: isCorrect ? undefined : APP_COLORS.fgRed, borderWidth: isCorrect ? undefined : '2px' }}
-        />
-      </div>
-    </DataLoader>
+    <div className='cc-fade-in cc-column mt-3'>
+      <PickSubstitutions
+        schemas={schemas}
+        prefixID={prefixes.dlg_cst_substitutes_list}
+        rows={8}
+        substitutions={substitutions}
+        setSubstitutions={setSubstitutions}
+        suggestions={suggestions}
+      />
+      <TextArea
+        disabled
+        value={validationText}
+        rows={4}
+        style={{ borderColor: isCorrect ? undefined : APP_COLORS.fgRed, borderWidth: isCorrect ? undefined : '2px' }}
+      />
+    </div>
   );
 }
 
diff --git a/rsconcept/frontend/src/dialogs/DlgEditReference/TabSyntacticReference.tsx b/rsconcept/frontend/src/dialogs/DlgEditReference/TabSyntacticReference.tsx
index 8bedad9a..dce9b1c1 100644
--- a/rsconcept/frontend/src/dialogs/DlgEditReference/TabSyntacticReference.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgEditReference/TabSyntacticReference.tsx
@@ -55,7 +55,7 @@ function TabSyntacticReference({ initial, onChangeValid, onChangeReference }: Ta
       />
       <TextInput
         id='dlg_main_ref'
-        disabled // prettier: split lines
+        disabled //
         dense
         noBorder
         label='Основная ссылка'
diff --git a/rsconcept/frontend/src/dialogs/DlgEditWordForms/DlgEditWordForms.tsx b/rsconcept/frontend/src/dialogs/DlgEditWordForms/DlgEditWordForms.tsx
index caaf05ec..07e6b39b 100644
--- a/rsconcept/frontend/src/dialogs/DlgEditWordForms/DlgEditWordForms.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgEditWordForms/DlgEditWordForms.tsx
@@ -3,14 +3,17 @@
 import clsx from 'clsx';
 import { useEffect, useState } from 'react';
 
+import { useIsProcessingCctext } from '@/backend/cctext/useIsProcessingCctext';
+import { useGenerateLexeme } from '@/backend/cctext/useGenerateLexeme';
+import { useInflectText } from '@/backend/cctext/useInflectText';
+import { useParseText } from '@/backend/cctext/useParseText';
 import { IconAccept, IconMoveDown, IconMoveLeft, IconMoveRight, IconRemove } from '@/components/Icons';
 import SelectMultiGrammeme from '@/components/select/SelectMultiGrammeme';
 import Label from '@/components/ui/Label';
 import MiniButton from '@/components/ui/MiniButton';
 import Modal from '@/components/ui/Modal';
 import TextArea from '@/components/ui/TextArea';
-import useConceptText from '@/hooks/useConceptText';
-import { Grammeme, ITextRequest, IWordForm, IWordFormPlain } from '@/models/language';
+import { Grammeme, IWordForm, IWordFormPlain } from '@/models/language';
 import { parseGrammemes, wordFormEquals } from '@/models/languageAPI';
 import { HelpTopic } from '@/models/miscellaneous';
 import { IConstituenta, TermForm } from '@/models/rsform';
@@ -27,7 +30,10 @@ export interface DlgEditWordFormsProps {
 
 function DlgEditWordForms() {
   const { target, onSave } = useDialogsStore(state => state.props as DlgEditWordFormsProps);
-  const textProcessor = useConceptText();
+  const isProcessing = useIsProcessingCctext();
+  const { inflectText } = useInflectText();
+  const { parseText } = useParseText();
+  const { generateLexeme } = useGenerateLexeme();
 
   const [term, setTerm] = useState('');
   const [inputText, setInputText] = useState('');
@@ -77,14 +83,11 @@ function DlgEditWordForms() {
       text: term,
       grams: inputGrams.map(gram => gram.value).join(',')
     };
-    textProcessor.inflect(data, response => setInputText(response.result));
+    inflectText(data, response => setInputText(response.result));
   }
 
   function handleParse() {
-    const data: ITextRequest = {
-      text: inputText
-    };
-    textProcessor.parse(data, response => {
+    parseText({ text: inputText }, response => {
       const grams = parseGrammemes(response.result);
       setInputGrams(SelectorGrammemes.filter(gram => grams.find(test => test === gram.value)));
     });
@@ -96,10 +99,7 @@ function DlgEditWordForms() {
         return;
       }
     }
-    const data: ITextRequest = {
-      text: inputText
-    };
-    textProcessor.generateLexeme(data, response => {
+    generateLexeme({ text: inputText }, response => {
       const lexeme: IWordForm[] = [];
       response.items.forEach(form => {
         const newForm: IWordForm = {
@@ -155,14 +155,14 @@ function DlgEditWordForms() {
             noHover
             title='Определить граммемы'
             icon={<IconMoveRight size='1.25rem' className='icon-primary' />}
-            disabled={textProcessor.processing || !inputText}
+            disabled={isProcessing || !inputText}
             onClick={handleParse}
           />
           <MiniButton
             noHover
             title='Генерировать словоформу'
             icon={<IconMoveLeft size='1.25rem' className='icon-primary' />}
-            disabled={textProcessor.processing || inputGrams.length == 0}
+            disabled={isProcessing || inputGrams.length == 0}
             onClick={handleInflect}
           />
         </div>
@@ -180,14 +180,14 @@ function DlgEditWordForms() {
             noHover
             title='Внести словоформу'
             icon={<IconAccept size='1.5rem' className='icon-green' />}
-            disabled={textProcessor.processing || !inputText || inputGrams.length == 0}
+            disabled={isProcessing || !inputText || inputGrams.length == 0}
             onClick={handleAddForm}
           />
           <MiniButton
             noHover
             title='Генерировать стандартные словоформы'
             icon={<IconMoveDown size='1.5rem' className='icon-primary' />}
-            disabled={textProcessor.processing || !inputText}
+            disabled={isProcessing || !inputText}
             onClick={handleGenerateLexeme}
           />
         </div>
@@ -198,7 +198,7 @@ function DlgEditWordForms() {
             title='Сбросить все словоформы'
             className='py-0'
             icon={<IconRemove size='1.5rem' className='icon-red' />}
-            disabled={textProcessor.processing || forms.length === 0}
+            disabled={isProcessing || forms.length === 0}
             onClick={handleResetAll}
           />
         </div>
diff --git a/rsconcept/frontend/src/dialogs/DlgInlineSynthesis/DlgInlineSynthesis.tsx b/rsconcept/frontend/src/dialogs/DlgInlineSynthesis/DlgInlineSynthesis.tsx
index b99b0f9b..2bf6eefd 100644
--- a/rsconcept/frontend/src/dialogs/DlgInlineSynthesis/DlgInlineSynthesis.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgInlineSynthesis/DlgInlineSynthesis.tsx
@@ -4,12 +4,13 @@ import clsx from 'clsx';
 import { useEffect, useState } from 'react';
 import { TabList, TabPanel, Tabs } from 'react-tabs';
 
+import { IInlineSynthesisDTO } from '@/backend/rsform/api';
+import { useRSForm } from '@/backend/rsform/useRSForm';
 import Modal from '@/components/ui/Modal';
 import TabLabel from '@/components/ui/TabLabel';
-import useRSFormDetails from '@/hooks/useRSFormDetails';
 import { LibraryItemID } from '@/models/library';
 import { ICstSubstitute } from '@/models/oss';
-import { ConstituentaID, IInlineSynthesisData, IRSForm } from '@/models/rsform';
+import { ConstituentaID, IRSForm } from '@/models/rsform';
 import { useDialogsStore } from '@/stores/dialogs';
 
 import TabConstituents from './TabConstituents';
@@ -18,7 +19,7 @@ import TabSubstitutions from './TabSubstitutions';
 
 export interface DlgInlineSynthesisProps {
   receiver: IRSForm;
-  onInlineSynthesis: (data: IInlineSynthesisData) => void;
+  onInlineSynthesis: (data: IInlineSynthesisDTO) => void;
 }
 
 export enum TabID {
@@ -35,7 +36,7 @@ function DlgInlineSynthesis() {
   const [selected, setSelected] = useState<ConstituentaID[]>([]);
   const [substitutions, setSubstitutions] = useState<ICstSubstitute[]>([]);
 
-  const source = useRSFormDetails({ target: donorID ? String(donorID) : undefined });
+  const source = useRSForm({ itemID: donorID });
 
   const validated = !!source.schema && selected.length > 0;
 
@@ -43,13 +44,12 @@ function DlgInlineSynthesis() {
     if (!source.schema) {
       return;
     }
-    const data: IInlineSynthesisData = {
+    onInlineSynthesis({
       source: source.schema?.id,
       receiver: receiver.id,
       items: selected,
       substitutions: substitutions
-    };
-    onInlineSynthesis(data);
+    });
   }
 
   useEffect(() => {
@@ -84,7 +84,7 @@ function DlgInlineSynthesis() {
         <TabPanel>
           <TabConstituents
             schema={source.schema}
-            loading={source.loading}
+            loading={source.isLoading}
             selected={selected}
             setSelected={setSelected}
           />
@@ -95,7 +95,7 @@ function DlgInlineSynthesis() {
             receiver={receiver}
             source={source.schema}
             selected={selected}
-            loading={source.loading}
+            loading={source.isLoading}
             substitutions={substitutions}
             setSubstitutions={setSubstitutions}
           />
diff --git a/rsconcept/frontend/src/dialogs/DlgInlineSynthesis/TabSchema.tsx b/rsconcept/frontend/src/dialogs/DlgInlineSynthesis/TabSchema.tsx
index 05d28c52..b4e604e3 100644
--- a/rsconcept/frontend/src/dialogs/DlgInlineSynthesis/TabSchema.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgInlineSynthesis/TabSchema.tsx
@@ -1,8 +1,8 @@
 'use client';
 
+import { useLibrary } from '@/backend/library/useLibrary';
 import PickSchema from '@/components/select/PickSchema';
 import TextInput from '@/components/ui/TextInput';
-import { useLibrary } from '@/context/LibraryContext';
 import { LibraryItemID, LibraryItemType } from '@/models/library';
 import { IRSForm } from '@/models/rsform';
 import { sortItemsForInlineSynthesis } from '@/models/rsformAPI';
@@ -14,14 +14,13 @@ interface TabSchemaProps {
 }
 
 function TabSchema({ selected, receiver, setSelected }: TabSchemaProps) {
-  const library = useLibrary();
-  const selectedInfo = library.items.find(item => item.id === selected);
-  const sortedItems = sortItemsForInlineSynthesis(receiver, library.items);
-
+  const { items: libraryItems } = useLibrary();
+  const selectedInfo = libraryItems.find(item => item.id === selected);
+  const sortedItems = sortItemsForInlineSynthesis(receiver, libraryItems);
   return (
     <div className='cc-fade-in flex flex-col'>
       <PickSchema
-        id='dlg_schema_picker' // prettier: split lines
+        id='dlg_schema_picker' //
         items={sortedItems}
         itemType={LibraryItemType.RSFORM}
         rows={14}
diff --git a/rsconcept/frontend/src/dialogs/DlgRelocateConstituents.tsx b/rsconcept/frontend/src/dialogs/DlgRelocateConstituents.tsx
index 2e599de5..75077fa4 100644
--- a/rsconcept/frontend/src/dialogs/DlgRelocateConstituents.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgRelocateConstituents.tsx
@@ -3,17 +3,18 @@
 import clsx from 'clsx';
 import { useState } from 'react';
 
+import { useLibrary } from '@/backend/library/useLibrary';
+import { ICstRelocateDTO } from '@/backend/oss/api';
+import { useRSForm } from '@/backend/rsform/useRSForm';
 import { RelocateUpIcon } from '@/components/DomainIcons';
 import PickMultiConstituenta from '@/components/select/PickMultiConstituenta';
 import SelectLibraryItem from '@/components/select/SelectLibraryItem';
 import MiniButton from '@/components/ui/MiniButton';
 import Modal from '@/components/ui/Modal';
 import DataLoader from '@/components/wrap/DataLoader';
-import { useLibrary } from '@/context/LibraryContext';
-import useRSFormDetails from '@/hooks/useRSFormDetails';
 import { ILibraryItem, LibraryItemID } from '@/models/library';
 import { HelpTopic } from '@/models/miscellaneous';
-import { ICstRelocateData, IOperation, IOperationSchema } from '@/models/oss';
+import { IOperation, IOperationSchema } from '@/models/oss';
 import { getRelocateCandidates } from '@/models/ossAPI';
 import { ConstituentaID } from '@/models/rsform';
 import { useDialogsStore } from '@/stores/dialogs';
@@ -22,23 +23,23 @@ import { prefixes } from '@/utils/constants';
 export interface DlgRelocateConstituentsProps {
   oss: IOperationSchema;
   initialTarget?: IOperation;
-  onSubmit: (data: ICstRelocateData) => void;
+  onSubmit: (data: ICstRelocateDTO) => void;
 }
 
 function DlgRelocateConstituents() {
   const { oss, initialTarget, onSubmit } = useDialogsStore(state => state.props as DlgRelocateConstituentsProps);
-  const library = useLibrary();
+  const { items: libraryItems } = useLibrary();
 
   const [directionUp, setDirectionUp] = useState(true);
   const [destination, setDestination] = useState<ILibraryItem | undefined>(undefined);
   const [selected, setSelected] = useState<ConstituentaID[]>([]);
   const [source, setSource] = useState<ILibraryItem | undefined>(
-    library.items.find(item => item.id === initialTarget?.result)
+    libraryItems.find(item => item.id === initialTarget?.result)
   );
   const isValid = !!destination && selected.length > 0;
 
   const operation = oss.items.find(item => item.result === source?.id);
-  const sourceSchemas = library.items.filter(item => oss.schemas.includes(item.id));
+  const sourceSchemas = libraryItems.filter(item => oss.schemas.includes(item.id));
   const destinationSchemas = (() => {
     if (!operation) {
       return [];
@@ -47,10 +48,10 @@ function DlgRelocateConstituents() {
     const ids: LibraryItemID[] = directionUp
       ? node.inputs.map(id => oss.operationByID.get(id)!.result).filter(id => id !== null)
       : node.outputs.map(id => oss.operationByID.get(id)!.result).filter(id => id !== null);
-    return ids.map(id => library.items.find(item => item.id === id)).filter(item => item !== undefined);
+    return ids.map(id => libraryItems.find(item => item.id === id)).filter(item => item !== undefined);
   })();
 
-  const sourceData = useRSFormDetails({ target: source ? String(source.id) : undefined });
+  const sourceData = useRSForm({ itemID: source?.id });
   const filteredConstituents = (() => {
     if (!sourceData.schema || !destination || !operation) {
       return [];
@@ -79,11 +80,10 @@ function DlgRelocateConstituents() {
     if (!destination) {
       return;
     }
-    const data: ICstRelocateData = {
+    onSubmit({
       destination: destination.id,
       items: selected
-    };
-    onSubmit(data);
+    });
   }
 
   return (
@@ -119,7 +119,7 @@ function DlgRelocateConstituents() {
             onSelectValue={handleSelectDestination}
           />
         </div>
-        <DataLoader isLoading={sourceData.loading} error={sourceData.error}>
+        <DataLoader isLoading={sourceData.isLoading} error={sourceData.error}>
           {sourceData.schema ? (
             <PickMultiConstituenta
               noBorder
diff --git a/rsconcept/frontend/src/dialogs/DlgRenameCst.tsx b/rsconcept/frontend/src/dialogs/DlgRenameCst.tsx
index 423235af..c587f098 100644
--- a/rsconcept/frontend/src/dialogs/DlgRenameCst.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgRenameCst.tsx
@@ -3,12 +3,13 @@
 import clsx from 'clsx';
 import { useEffect, useState } from 'react';
 
+import { ICstRenameDTO } from '@/backend/rsform/api';
 import Modal from '@/components/ui/Modal';
 import SelectSingle from '@/components/ui/SelectSingle';
 import TextInput from '@/components/ui/TextInput';
 import usePartialUpdate from '@/hooks/usePartialUpdate';
 import { HelpTopic } from '@/models/miscellaneous';
-import { CstType, ICstRenameData, IRSForm } from '@/models/rsform';
+import { CstType, IRSForm } from '@/models/rsform';
 import { generateAlias, validateNewAlias } from '@/models/rsformAPI';
 import { useDialogsStore } from '@/stores/dialogs';
 import { labelCstType } from '@/utils/labels';
@@ -16,9 +17,9 @@ import { SelectorCstType } from '@/utils/selectors';
 
 export interface DlgRenameCstProps {
   schema: IRSForm;
-  initial: ICstRenameData;
+  initial: ICstRenameDTO;
   allowChangeType: boolean;
-  onRename: (data: ICstRenameData) => void;
+  onRename: (data: ICstRenameDTO) => void;
 }
 
 function DlgRenameCst() {
diff --git a/rsconcept/frontend/src/dialogs/DlgSubstituteCst.tsx b/rsconcept/frontend/src/dialogs/DlgSubstituteCst.tsx
index 21a017b4..03eff13a 100644
--- a/rsconcept/frontend/src/dialogs/DlgSubstituteCst.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgSubstituteCst.tsx
@@ -6,14 +6,14 @@ import { useState } from 'react';
 import PickSubstitutions from '@/components/select/PickSubstitutions';
 import Modal from '@/components/ui/Modal';
 import { HelpTopic } from '@/models/miscellaneous';
-import { ICstSubstitute, ICstSubstituteData } from '@/models/oss';
+import { ICstSubstitute, ICstSubstitutions } from '@/models/oss';
 import { IRSForm } from '@/models/rsform';
 import { useDialogsStore } from '@/stores/dialogs';
 import { prefixes } from '@/utils/constants';
 
 export interface DlgSubstituteCstProps {
   schema: IRSForm;
-  onSubstitute: (data: ICstSubstituteData) => void;
+  onSubstitute: (data: ICstSubstitutions) => void;
 }
 
 function DlgSubstituteCst() {
@@ -22,7 +22,7 @@ function DlgSubstituteCst() {
   const canSubmit = substitutions.length > 0;
 
   function handleSubmit() {
-    const data: ICstSubstituteData = {
+    const data: ICstSubstitutions = {
       substitutions: substitutions
     };
     onSubstitute(data);
diff --git a/rsconcept/frontend/src/dialogs/DlgUploadRSForm.tsx b/rsconcept/frontend/src/dialogs/DlgUploadRSForm.tsx
index ef31a68b..be37a576 100644
--- a/rsconcept/frontend/src/dialogs/DlgUploadRSForm.tsx
+++ b/rsconcept/frontend/src/dialogs/DlgUploadRSForm.tsx
@@ -3,19 +3,22 @@
 import { useState } from 'react';
 import { toast } from 'react-toastify';
 
+import { IRSFormUploadDTO } from '@/backend/rsform/api';
+import { useUploadTRS } from '@/backend/rsform/useUploadTRS';
 import Checkbox from '@/components/ui/Checkbox';
 import FileInput from '@/components/ui/FileInput';
 import Modal from '@/components/ui/Modal';
-import { IRSFormUploadData } from '@/models/rsform';
+import { LibraryItemID } from '@/models/library';
 import { useDialogsStore } from '@/stores/dialogs';
 import { EXTEOR_TRS_FILE } from '@/utils/constants';
 
 export interface DlgUploadRSFormProps {
-  upload: (data: IRSFormUploadData, callback: () => void) => void;
+  itemID: LibraryItemID;
 }
 
 function DlgUploadRSForm() {
-  const { upload } = useDialogsStore(state => state.props as DlgUploadRSFormProps);
+  const { itemID } = useDialogsStore(state => state.props as DlgUploadRSFormProps);
+  const { upload } = useUploadTRS();
   const [loadMetadata, setLoadMetadata] = useState(false);
   const [file, setFile] = useState<File | undefined>();
 
@@ -23,7 +26,8 @@ function DlgUploadRSForm() {
     if (!file) {
       return;
     }
-    const data: IRSFormUploadData = {
+    const data: IRSFormUploadDTO = {
+      itemID: itemID,
       load_metadata: loadMetadata,
       file: file,
       fileName: file.name
diff --git a/rsconcept/frontend/src/hooks/useCheckConstituenta.ts b/rsconcept/frontend/src/hooks/useCheckConstituenta.ts
deleted file mode 100644
index 8b15aff4..00000000
--- a/rsconcept/frontend/src/hooks/useCheckConstituenta.ts
+++ /dev/null
@@ -1,40 +0,0 @@
-'use client';
-
-import { useCallback, useState } from 'react';
-
-import { DataCallback } from '@/backend/apiTransport';
-import { postCheckConstituenta } from '@/backend/rsforms';
-import { type ErrorData } from '@/components/info/InfoError';
-import { ICheckConstituentaData, IConstituenta, type IRSForm } from '@/models/rsform';
-import { IExpressionParse } from '@/models/rslang';
-
-function useCheckConstituenta({ schema }: { schema?: IRSForm }) {
-  const [processing, setProcessing] = useState(false);
-  const [error, setError] = useState<ErrorData>(undefined);
-  const [parseData, setParseData] = useState<IExpressionParse | undefined>(undefined);
-
-  const resetParse = useCallback(() => setParseData(undefined), []);
-
-  function checkConstituenta(expression: string, activeCst: IConstituenta, onSuccess?: DataCallback<IExpressionParse>) {
-    const data: ICheckConstituentaData = {
-      definition_formal: expression,
-      alias: activeCst.alias,
-      cst_type: activeCst.cst_type
-    };
-    setError(undefined);
-    postCheckConstituenta(String(schema!.id), {
-      data: data,
-      showError: true,
-      setLoading: setProcessing,
-      onError: setError,
-      onSuccess: parse => {
-        setParseData(parse);
-        onSuccess?.(parse);
-      }
-    });
-  }
-
-  return { parseData, checkConstituenta, resetParse, error, setError, processing };
-}
-
-export default useCheckConstituenta;
diff --git a/rsconcept/frontend/src/hooks/useConceptText.ts b/rsconcept/frontend/src/hooks/useConceptText.ts
deleted file mode 100644
index 3dc08abd..00000000
--- a/rsconcept/frontend/src/hooks/useConceptText.ts
+++ /dev/null
@@ -1,56 +0,0 @@
-'use client';
-
-import { useCallback, useState } from 'react';
-
-import { DataCallback } from '@/backend/apiTransport';
-import { postGenerateLexeme, postInflectText, postParseText } from '@/backend/cctext';
-import { ErrorData } from '@/components/info/InfoError';
-import { ILexemeData, ITextRequest, ITextResult, IWordFormPlain } from '@/models/language';
-
-function useConceptText() {
-  const [processing, setProcessing] = useState(false);
-  const [error, setError] = useState<ErrorData>(undefined);
-
-  const inflect = useCallback((data: IWordFormPlain, onSuccess: DataCallback<ITextResult>) => {
-    setError(undefined);
-    postInflectText({
-      data: data,
-      showError: true,
-      setLoading: setProcessing,
-      onError: setError,
-      onSuccess: data => {
-        onSuccess?.(data);
-      }
-    });
-  }, []);
-
-  const parse = useCallback((data: ITextRequest, onSuccess: DataCallback<ITextResult>) => {
-    setError(undefined);
-    postParseText({
-      data: data,
-      showError: true,
-      setLoading: setProcessing,
-      onError: setError,
-      onSuccess: data => {
-        onSuccess?.(data);
-      }
-    });
-  }, []);
-
-  const generateLexeme = useCallback((data: ITextRequest, onSuccess: DataCallback<ILexemeData>) => {
-    setError(undefined);
-    postGenerateLexeme({
-      data: data,
-      showError: true,
-      setLoading: setProcessing,
-      onError: setError,
-      onSuccess: data => {
-        onSuccess?.(data);
-      }
-    });
-  }, []);
-
-  return { inflect, parse, generateLexeme, error, setError, processing };
-}
-
-export default useConceptText;
diff --git a/rsconcept/frontend/src/hooks/useOssDetails.ts b/rsconcept/frontend/src/hooks/useOssDetails.ts
deleted file mode 100644
index 44be1ecf..00000000
--- a/rsconcept/frontend/src/hooks/useOssDetails.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-'use client';
-
-import { useCallback, useEffect, useState } from 'react';
-
-import { useAuth } from '@/backend/auth/useAuth';
-import { getOssDetails } from '@/backend/oss';
-import { type ErrorData } from '@/components/info/InfoError';
-import { useLibrary } from '@/context/LibraryContext';
-import { IOperationSchema, IOperationSchemaData } from '@/models/oss';
-import { OssLoader } from '@/models/OssLoader';
-
-function useOssDetails({ target }: { target?: string }) {
-  const { isLoading: userLoading } = useAuth();
-  const library = useLibrary();
-  const [schema, setInner] = useState<IOperationSchema | undefined>(undefined);
-  const [loading, setLoading] = useState(target != undefined);
-  const [error, setError] = useState<ErrorData>(undefined);
-
-  const setSchema = useCallback(
-    (data?: IOperationSchemaData) => {
-      if (!data) {
-        setInner(undefined);
-        return;
-      }
-      const newSchema = new OssLoader(data, library.items).produceOSS();
-      setInner(newSchema);
-    },
-    [library.items]
-  );
-
-  function partialUpdate(data: Partial<IOperationSchema>) {
-    setInner(prev => (prev ? { ...prev, ...data } : prev));
-  }
-
-  const reload = useCallback(
-    (setCustomLoading?: typeof setLoading, callback?: () => void) => {
-      setError(undefined);
-      if (!target) {
-        return;
-      }
-      getOssDetails(target, {
-        showError: true,
-        setLoading: setCustomLoading ?? setLoading,
-        onError: error => {
-          setInner(undefined);
-          setError(error);
-        },
-        onSuccess: schema => {
-          setSchema(schema);
-          callback?.();
-        }
-      });
-    },
-    [target, setSchema]
-  );
-
-  useEffect(() => {
-    if (!userLoading && !library.loading && library.items.length > 0) {
-      reload();
-    }
-  }, [reload, userLoading, library.loading, library.items]);
-
-  return { schema, setSchema, partialUpdate, reload, error, setError, loading };
-}
-
-export default useOssDetails;
diff --git a/rsconcept/frontend/src/hooks/useRSFormCache.ts b/rsconcept/frontend/src/hooks/useRSFormCache.ts
deleted file mode 100644
index 539e70b9..00000000
--- a/rsconcept/frontend/src/hooks/useRSFormCache.ts
+++ /dev/null
@@ -1,56 +0,0 @@
-'use client';
-
-import { useCallback, useEffect, useMemo, useState } from 'react';
-
-import { getRSFormDetails } from '@/backend/rsforms';
-import { type ErrorData } from '@/components/info/InfoError';
-import { LibraryItemID } from '@/models/library';
-import { IRSForm, IRSFormData } from '@/models/rsform';
-import { RSFormLoader } from '@/models/RSFormLoader';
-
-function useRSFormCache() {
-  const [cache, setCache] = useState<IRSForm[]>([]);
-  const [pending, setPending] = useState<LibraryItemID[]>([]);
-  const [processing, setProcessing] = useState<LibraryItemID[]>([]);
-  const loading = useMemo(() => pending.length > 0 || processing.length > 0, [pending, processing]);
-  const [error, setError] = useState<ErrorData>(undefined);
-
-  function setSchema(data: IRSFormData) {
-    const schema = new RSFormLoader(data).produceRSForm();
-    setCache(prev => [...prev, schema]);
-  }
-
-  const preload = useCallback(
-    (target: LibraryItemID[]) => setPending(prev => [...prev, ...target.filter(id => !prev.includes(id))]),
-    []
-  );
-
-  useEffect(() => {
-    if (pending.length === 0) {
-      return;
-    }
-    const ids = pending.filter(id => !processing.includes(id) && !cache.find(schema => schema.id === id));
-    setPending([]);
-    if (ids.length === 0) {
-      return;
-    }
-    setProcessing(prev => [...prev, ...ids]);
-    ids.forEach(id =>
-      getRSFormDetails(String(id), '', {
-        showError: false,
-        onError: error => {
-          setProcessing(prev => prev.filter(item => item !== id));
-          setError(error);
-        },
-        onSuccess: data => {
-          setProcessing(prev => prev.filter(item => item !== id));
-          setSchema(data);
-        }
-      })
-    );
-  }, [pending, cache, processing]);
-
-  return { preload, data: cache, loading, error, setError };
-}
-
-export default useRSFormCache;
diff --git a/rsconcept/frontend/src/hooks/useRSFormDetails.ts b/rsconcept/frontend/src/hooks/useRSFormDetails.ts
deleted file mode 100644
index 603acfef..00000000
--- a/rsconcept/frontend/src/hooks/useRSFormDetails.ts
+++ /dev/null
@@ -1,61 +0,0 @@
-'use client';
-
-import { useCallback, useEffect, useState } from 'react';
-
-import { useAuth } from '@/backend/auth/useAuth';
-import { getRSFormDetails } from '@/backend/rsforms';
-import { type ErrorData } from '@/components/info/InfoError';
-import { IRSForm, IRSFormData } from '@/models/rsform';
-import { RSFormLoader } from '@/models/RSFormLoader';
-
-function useRSFormDetails({ target, version }: { target?: string; version?: string }) {
-  const { isLoading: userLoading } = useAuth();
-  const [schema, setInnerSchema] = useState<IRSForm | undefined>(undefined);
-  const [loading, setLoading] = useState(target != undefined);
-  const [error, setError] = useState<ErrorData>(undefined);
-
-  function setSchema(data?: IRSFormData) {
-    if (!data) {
-      setInnerSchema(undefined);
-      return;
-    }
-    const schema = new RSFormLoader(data).produceRSForm();
-    setInnerSchema(schema);
-  }
-
-  function partialUpdate(data: Partial<IRSForm>) {
-    setInnerSchema(prev => (prev ? { ...prev, ...data } : prev));
-  }
-
-  const reload = useCallback(
-    (setCustomLoading?: typeof setLoading, callback?: () => void) => {
-      setError(undefined);
-      if (!target) {
-        return;
-      }
-      getRSFormDetails(target, version ?? '', {
-        showError: true,
-        setLoading: setCustomLoading ?? setLoading,
-        onError: error => {
-          setInnerSchema(undefined);
-          setError(error);
-        },
-        onSuccess: schema => {
-          setSchema(schema);
-          callback?.();
-        }
-      });
-    },
-    [target, version]
-  );
-
-  useEffect(() => {
-    if (!userLoading) {
-      reload();
-    }
-  }, [reload, userLoading]);
-
-  return { schema, setSchema, partialUpdate, reload, error, setError, loading };
-}
-
-export default useRSFormDetails;
diff --git a/rsconcept/frontend/src/hooks/useRSParse.ts b/rsconcept/frontend/src/hooks/useRSParse.ts
new file mode 100644
index 00000000..734db902
--- /dev/null
+++ b/rsconcept/frontend/src/hooks/useRSParse.ts
@@ -0,0 +1,32 @@
+'use client';
+
+import { useCallback, useState } from 'react';
+
+import { DataCallback } from '@/backend/apiTransport';
+import { ICheckConstituentaDTO } from '@/backend/rsform/api';
+import { useCheckConstituenta } from '@/backend/rsform/useCheckConstituenta';
+import { IConstituenta, type IRSForm } from '@/models/rsform';
+import { IExpressionParse } from '@/models/rslang';
+
+function useRSParse({ schema }: { schema?: IRSForm }) {
+  const [parseData, setParseData] = useState<IExpressionParse | undefined>(undefined);
+
+  const resetParse = useCallback(() => setParseData(undefined), []);
+  const { checkConstituenta: checkInternal, isPending, error, reset } = useCheckConstituenta();
+
+  function checkConstituenta(expression: string, activeCst: IConstituenta, onSuccess?: DataCallback<IExpressionParse>) {
+    const data: ICheckConstituentaDTO = {
+      definition_formal: expression,
+      alias: activeCst.alias,
+      cst_type: activeCst.cst_type
+    };
+    checkInternal({ itemID: schema!.id, data }, parse => {
+      setParseData(parse);
+      onSuccess?.(parse);
+    });
+  }
+
+  return { parseData, checkConstituenta, resetParse, error, reset, isPending };
+}
+
+export default useRSParse;
diff --git a/rsconcept/frontend/src/models/language.ts b/rsconcept/frontend/src/models/language.ts
index f872aa86..09c706b2 100644
--- a/rsconcept/frontend/src/models/language.ts
+++ b/rsconcept/frontend/src/models/language.ts
@@ -2,13 +2,6 @@
  * Module: Natural language model declarations.
  */
 
-/**
- * Represents API result for text output.
- */
-export interface ITextResult {
-  result: string;
-}
-
 /**
  * Represents single unit of language Morphology.
  */
@@ -237,12 +230,6 @@ export interface ILexemeData {
 }
 
 // ====== Reference resolution =====
-/**
- * Represents text request.
- */
-export interface ITextRequest {
-  text: string;
-}
 
 /**
  * Represents text reference type.
diff --git a/rsconcept/frontend/src/models/library.ts b/rsconcept/frontend/src/models/library.ts
index 806a4acf..6f9f498d 100644
--- a/rsconcept/frontend/src/models/library.ts
+++ b/rsconcept/frontend/src/models/library.ts
@@ -2,7 +2,6 @@
  * Module: Models for LibraryItem.
  */
 
-import { ConstituentaID } from './rsform';
 import { UserID } from './user';
 
 /**
@@ -59,13 +58,6 @@ export interface IVersionInfo {
  */
 export interface IVersionData extends Omit<IVersionInfo, 'id' | 'time_create'> {}
 
-/**
- * Create version metadata in persistent storage.
- */
-export interface IVersionCreateData extends IVersionData {
-  items?: ConstituentaID[];
-}
-
 /**
  * Represents library item common data typical for all item types.
  */
@@ -121,39 +113,3 @@ export interface ILibraryItemEditor {
 
   share: () => void;
 }
-
-/**
- * Represents update data for editing {@link ILibraryItem}.
- */
-export interface ILibraryUpdateData
-  extends Omit<ILibraryItem, 'time_create' | 'time_update' | 'access_policy' | 'location' | 'id' | 'owner'> {}
-
-/**
- * Represents update data for editing {@link AccessPolicy} of a {@link ILibraryItem}.
- */
-export interface ITargetAccessPolicy {
-  access_policy: AccessPolicy;
-}
-
-/**
- * Represents update data for editing Location of a {@link ILibraryItem}.
- */
-export interface ITargetLocation {
-  location: string;
-}
-
-/**
- * Represents update data for renaming Location.
- */
-export interface IRenameLocationData {
-  target: string;
-  new_location: string;
-}
-
-/**
- * Represents data, used for creating {@link IRSForm}.
- */
-export interface ILibraryCreateData extends Omit<ILibraryItem, 'time_create' | 'time_update' | 'id' | 'owner'> {
-  file?: File;
-  fileName?: string;
-}
diff --git a/rsconcept/frontend/src/models/oss.ts b/rsconcept/frontend/src/models/oss.ts
index 761cd9c6..6f1100f6 100644
--- a/rsconcept/frontend/src/models/oss.ts
+++ b/rsconcept/frontend/src/models/oss.ts
@@ -55,53 +55,10 @@ export interface IOperationPosition extends Pick<IOperation, 'id' | 'position_x'
 /**
  * Represents all {@link IOperation} positions in {@link IOperationSchema}.
  */
-export interface IPositionsData {
+export interface IPositions {
   positions: IOperationPosition[];
 }
 
-/**
- * Represents target {@link IOperation}.
- */
-export interface ITargetOperation extends IPositionsData {
-  target: OperationID;
-}
-
-/**
- * Represents {@link IOperation} data, used in creation process.
- */
-export interface IOperationCreateData extends IPositionsData {
-  item_data: Pick<
-    IOperation,
-    'alias' | 'operation_type' | 'title' | 'comment' | 'position_x' | 'position_y' | 'result'
-  >;
-  arguments: OperationID[] | undefined;
-  create_schema: boolean;
-}
-
-/**
- * Represents {@link IOperation} data, used in update process.
- */
-export interface IOperationUpdateData extends ITargetOperation {
-  item_data: Pick<IOperation, 'alias' | 'title' | 'comment'>;
-  arguments: OperationID[] | undefined;
-  substitutions: ICstSubstitute[] | undefined;
-}
-
-/**
- * Represents {@link IOperation} data, used in destruction process.
- */
-export interface IOperationDeleteData extends ITargetOperation {
-  keep_constituents: boolean;
-  delete_schema: boolean;
-}
-
-/**
- * Represents {@link IOperation} data, used in setInput process.
- */
-export interface IOperationSetInputData extends ITargetOperation {
-  input: LibraryItemID | null;
-}
-
 /**
  * Represents {@link IOperation} Argument.
  */
@@ -121,18 +78,10 @@ export interface ICstSubstitute {
 /**
  * Represents data, used in merging multiple {@link IConstituenta}.
  */
-export interface ICstSubstituteData {
+export interface ICstSubstitutions {
   substitutions: ICstSubstitute[];
 }
 
-/**
- * Represents data, used relocating {@link IConstituenta}s between {@link ILibraryItem}s.
- */
-export interface ICstRelocateData {
-  destination: LibraryItemID;
-  items: ConstituentaID[];
-}
-
 /**
  * Represents substitution for multi synthesis table.
  */
@@ -186,22 +135,6 @@ export interface IOperationSchema extends IOperationSchemaData {
   operationByID: Map<OperationID, IOperation>;
 }
 
-/**
- * Represents data response when creating {@link IOperation}.
- */
-export interface IOperationCreatedResponse {
-  new_operation: IOperationData;
-  oss: IOperationSchemaData;
-}
-
-/**
- * Represents data response when creating {@link IRSForm} for Input {@link IOperation}.
- */
-export interface IInputCreatedResponse {
-  new_schema: ILibraryItem;
-  oss: IOperationSchemaData;
-}
-
 /**
  * Represents substitution error description.
  */
diff --git a/rsconcept/frontend/src/models/rsform.ts b/rsconcept/frontend/src/models/rsform.ts
index 1f7c2e1b..5abb8f3d 100644
--- a/rsconcept/frontend/src/models/rsform.ts
+++ b/rsconcept/frontend/src/models/rsform.ts
@@ -4,8 +4,7 @@
 
 import { Graph } from '@/models/Graph';
 
-import { ILibraryItem, ILibraryItemReference, ILibraryItemVersioned, LibraryItemID } from './library';
-import { ICstSubstitute } from './oss';
+import { ILibraryItemReference, ILibraryItemVersioned, LibraryItemID } from './library';
 import { IArgumentInfo, ParsingStatus, ValueClass } from './rslang';
 
 /**
@@ -146,60 +145,6 @@ export interface IConstituentaList {
   items: ConstituentaID[];
 }
 
-/**
- * Represents {@link IConstituenta} data, used for checking expression.
- */
-export interface ICheckConstituentaData extends Pick<IConstituentaMeta, 'alias' | 'cst_type' | 'definition_formal'> {}
-
-/**
- * Represents {@link IConstituenta} data, used in creation process.
- */
-export interface ICstCreateData
-  extends Pick<
-    IConstituentaMeta,
-    'alias' | 'cst_type' | 'definition_raw' | 'term_raw' | 'convention' | 'definition_formal' | 'term_forms'
-  > {
-  insert_after: ConstituentaID | null;
-}
-
-/**
- * Represents data, used in ordering a list of {@link IConstituenta}.
- */
-export interface ICstMovetoData extends IConstituentaList {
-  move_to: number; // Note: 0-base index
-}
-
-/**
- * Represents data, used in updating persistent attributes in {@link IConstituenta}.
- */
-export interface ICstUpdateData {
-  target: ConstituentaID;
-  item_data: Partial<
-    Pick<IConstituentaMeta, 'convention' | 'definition_formal' | 'definition_raw' | 'term_raw' | 'term_forms'>
-  >;
-}
-
-/**
- * Represents data, used in renaming {@link IConstituenta}.
- */
-export interface ICstRenameData extends ITargetCst, Pick<IConstituentaMeta, 'alias' | 'cst_type'> {}
-
-/**
- * Represents data response when creating {@link IConstituenta}.
- */
-export interface ICstCreatedResponse {
-  new_cst: IConstituentaMeta;
-  schema: IRSFormData;
-}
-
-/**
- * Represents data response when creating producing structure of {@link IConstituenta}.
- */
-export interface IProduceStructureResponse {
-  cst_list: ConstituentaID[];
-  schema: IRSFormData;
-}
-
 /**
  * Represents {@link IRSForm} statistics.
  */
@@ -254,30 +199,6 @@ export interface IRSForm extends IRSFormData {
   cstByID: Map<ConstituentaID, IConstituenta>;
 }
 
-/**
- * Represents data, used for cloning {@link IRSForm}.
- */
-export interface IRSFormCloneData extends Omit<ILibraryItem, 'time_create' | 'time_update' | 'id' | 'owner'> {
-  items?: ConstituentaID[];
-}
-
-/**
- * Represents data, used for uploading {@link IRSForm} as file.
- */
-export interface IRSFormUploadData {
-  load_metadata: boolean;
-  file: File;
-  fileName: string;
-}
-
-/**
- * Represents data response when creating {@link IVersionInfo}.
- */
-export interface IVersionCreatedResponse {
-  version: number;
-  schema: IRSFormData;
-}
-
 /**
  * Represents single substitution for binary synthesis table.
  */
@@ -286,13 +207,3 @@ export interface IBinarySubstitution {
   rightCst: IConstituenta;
   deleteRight: boolean;
 }
-
-/**
- * Represents input data for inline synthesis.
- */
-export interface IInlineSynthesisData {
-  receiver: LibraryItemID;
-  source: LibraryItemID;
-  items: ConstituentaID[];
-  substitutions: ICstSubstitute[];
-}
diff --git a/rsconcept/frontend/src/models/user.ts b/rsconcept/frontend/src/models/user.ts
index 08fd9b03..98f37466 100644
--- a/rsconcept/frontend/src/models/user.ts
+++ b/rsconcept/frontend/src/models/user.ts
@@ -47,20 +47,6 @@ export interface IUserProfile extends Omit<IUser, 'is_staff'> {}
  */
 export interface IUserInfo extends Omit<IUserProfile, 'email' | 'username'> {}
 
-/**
- * Represents target {@link User}.
- */
-export interface ITargetUser {
-  user: UserID;
-}
-
-/**
- * Represents target multiple {@link User}.
- */
-export interface ITargetUsers {
-  users: UserID[];
-}
-
 /**
  * Represents user access mode.
  */
diff --git a/rsconcept/frontend/src/pages/CreateItemPage/FormCreateItem.tsx b/rsconcept/frontend/src/pages/CreateItemPage/FormCreateItem.tsx
index b5b712fc..eb9623b4 100644
--- a/rsconcept/frontend/src/pages/CreateItemPage/FormCreateItem.tsx
+++ b/rsconcept/frontend/src/pages/CreateItemPage/FormCreateItem.tsx
@@ -6,6 +6,8 @@ import { toast } from 'react-toastify';
 
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
+import { ILibraryCreateDTO } from '@/backend/library/api';
+import { useCreateItem } from '@/backend/library/useCreateItem';
 import { VisibilityIcon } from '@/components/DomainIcons';
 import { IconDownload } from '@/components/Icons';
 import InfoError from '@/components/info/InfoError';
@@ -20,10 +22,8 @@ import Overlay from '@/components/ui/Overlay';
 import SubmitButton from '@/components/ui/SubmitButton';
 import TextArea from '@/components/ui/TextArea';
 import TextInput from '@/components/ui/TextInput';
-import { useLibrary } from '@/context/LibraryContext';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { AccessPolicy, LibraryItemType, LocationHead } from '@/models/library';
-import { ILibraryCreateData } from '@/models/library';
 import { combineLocation, validateLocation } from '@/models/libraryAPI';
 import { useLibrarySearchStore } from '@/stores/librarySearch';
 import { EXTEOR_TRS_FILE } from '@/utils/constants';
@@ -32,7 +32,7 @@ import { information } from '@/utils/labels';
 function FormCreateItem() {
   const router = useConceptNavigation();
   const { user } = useAuth();
-  const { createItem, processingError, setProcessingError, processing, folders } = useLibrary();
+  const { createItem, isPending, error, reset } = useCreateItem();
 
   const searchLocation = useLibrarySearchStore(state => state.location);
   const setSearchLocation = useLibrarySearchStore(state => state.setLocation);
@@ -55,8 +55,8 @@ function FormCreateItem() {
   const inputRef = useRef<HTMLInputElement | null>(null);
 
   useEffect(() => {
-    setProcessingError(undefined);
-  }, [title, alias, setProcessingError]);
+    reset();
+  }, [title, alias, reset]);
 
   function handleCancel() {
     if (router.canBack()) {
@@ -68,10 +68,10 @@ function FormCreateItem() {
 
   function handleSubmit(event: React.FormEvent<HTMLFormElement>) {
     event.preventDefault();
-    if (processing) {
+    if (isPending) {
       return;
     }
-    const data: ILibraryCreateData = {
+    const data: ILibraryCreateDTO = {
       item_type: itemType,
       title: title,
       alias: alias,
@@ -205,7 +205,7 @@ function FormCreateItem() {
             excluded={!user?.is_staff ? [LocationHead.LIBRARY] : []}
           />
         </div>
-        <SelectLocationContext folderTree={folders} value={location} onChange={handleSelectLocation} />
+        <SelectLocationContext value={location} onChange={handleSelectLocation} />
         <TextArea
           id='dlg_cst_body'
           label='Путь'
@@ -216,10 +216,10 @@ function FormCreateItem() {
       </div>
 
       <div className='flex justify-around gap-6 py-3'>
-        <SubmitButton text='Создать схему' loading={processing} className='min-w-[10rem]' disabled={!isValid} />
+        <SubmitButton text='Создать схему' loading={isPending} className='min-w-[10rem]' disabled={!isValid} />
         <Button text='Отмена' className='min-w-[10rem]' onClick={() => handleCancel()} />
       </div>
-      {processingError ? <InfoError error={processingError} /> : null}
+      {error ? <InfoError error={error} /> : null}
     </form>
   );
 }
diff --git a/rsconcept/frontend/src/pages/HomePage.tsx b/rsconcept/frontend/src/pages/HomePage.tsx
index 102da9e3..2cb371a4 100644
--- a/rsconcept/frontend/src/pages/HomePage.tsx
+++ b/rsconcept/frontend/src/pages/HomePage.tsx
@@ -3,7 +3,7 @@ import { useEffect } from 'react';
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
 import Loader from '@/components/ui/Loader';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { PARAMETER } from '@/utils/constants';
 
 function HomePage() {
diff --git a/rsconcept/frontend/src/pages/LibraryPage/LibraryPage.tsx b/rsconcept/frontend/src/pages/LibraryPage/LibraryPage.tsx
index d098e635..f8191f02 100644
--- a/rsconcept/frontend/src/pages/LibraryPage/LibraryPage.tsx
+++ b/rsconcept/frontend/src/pages/LibraryPage/LibraryPage.tsx
@@ -3,15 +3,15 @@
 import fileDownload from 'js-file-download';
 import { toast } from 'react-toastify';
 
+import { useApplyLibraryFilter } from '@/backend/library/useApplyLibraryFilter';
+import { useLibrarySuspense } from '@/backend/library/useLibrary';
+import { useRenameLocation } from '@/backend/library/useRenameLocation';
 import { IconCSV } from '@/components/Icons';
 import MiniButton from '@/components/ui/MiniButton';
 import Overlay from '@/components/ui/Overlay';
-import DataLoader from '@/components/wrap/DataLoader';
-import { useLibrary } from '@/context/LibraryContext';
-import { IRenameLocationData } from '@/models/library';
 import { useAppLayoutStore } from '@/stores/appLayout';
 import { useDialogsStore } from '@/stores/dialogs';
-import { useLibraryFilter, useLibrarySearchStore } from '@/stores/librarySearch';
+import { useCreateLibraryFilter, useLibrarySearchStore } from '@/stores/librarySearch';
 import { information } from '@/utils/labels';
 import { convertToCSV } from '@/utils/utils';
 
@@ -20,35 +20,39 @@ import ToolbarSearch from './ToolbarSearch';
 import ViewSideLocation from './ViewSideLocation';
 
 function LibraryPage() {
-  const library = useLibrary();
+  const { items: libraryItems } = useLibrarySuspense();
+  const { renameLocation } = useRenameLocation();
+
   const noNavigation = useAppLayoutStore(state => state.noNavigation);
 
   const folderMode = useLibrarySearchStore(state => state.folderMode);
   const location = useLibrarySearchStore(state => state.location);
   const setLocation = useLibrarySearchStore(state => state.setLocation);
 
-  const filter = useLibraryFilter();
-  const items = library.applyFilter(filter);
+  const filter = useCreateLibraryFilter();
+  const { filtered } = useApplyLibraryFilter(filter);
 
   const showChangeLocation = useDialogsStore(state => state.showChangeLocation);
 
   function handleRenameLocation(newLocation: string) {
-    const data: IRenameLocationData = {
-      target: location,
-      new_location: newLocation
-    };
-    library.renameLocation(data, () => {
-      setLocation(newLocation);
-      toast.success(information.locationRenamed);
-    });
+    renameLocation(
+      {
+        target: location,
+        new_location: newLocation
+      },
+      () => {
+        setLocation(newLocation);
+        toast.success(information.locationRenamed);
+      }
+    );
   }
 
   function handleDownloadCSV() {
-    if (items.length === 0) {
+    if (filtered.length === 0) {
       toast.error(information.noDataToExport);
       return;
     }
-    const blob = convertToCSV(items);
+    const blob = convertToCSV(filtered);
     try {
       fileDownload(blob, 'library.csv', 'text/csv;charset=utf-8;');
     } catch (error) {
@@ -57,7 +61,7 @@ function LibraryPage() {
   }
 
   return (
-    <DataLoader isLoading={library.loading} error={library.loadingError} hasNoData={library.items.length === 0}>
+    <>
       <Overlay
         position={noNavigation ? 'top-[0.25rem] right-[3rem]' : 'top-[0.25rem] right-0'}
         layer='z-tooltip'
@@ -69,18 +73,17 @@ function LibraryPage() {
           onClick={handleDownloadCSV}
         />
       </Overlay>
-      <ToolbarSearch total={library.items.length ?? 0} filtered={items.length} />
+      <ToolbarSearch total={libraryItems.length} filtered={filtered.length} />
 
       <div className='cc-fade-in flex'>
         <ViewSideLocation
           isVisible={folderMode}
-          folderTree={library.folders}
           onRenameLocation={() => showChangeLocation({ initial: location, onChangeLocation: handleRenameLocation })}
         />
 
-        <TableLibraryItems items={items} />
+        <TableLibraryItems items={filtered} />
       </div>
-    </DataLoader>
+    </>
   );
 }
 
diff --git a/rsconcept/frontend/src/pages/LibraryPage/TableLibraryItems.tsx b/rsconcept/frontend/src/pages/LibraryPage/TableLibraryItems.tsx
index d11f0ea0..ce02cf5a 100644
--- a/rsconcept/frontend/src/pages/LibraryPage/TableLibraryItems.tsx
+++ b/rsconcept/frontend/src/pages/LibraryPage/TableLibraryItems.tsx
@@ -13,7 +13,7 @@ import DataTable, { createColumnHelper, IConditionalStyle, VisibilityState } fro
 import FlexColumn from '@/components/ui/FlexColumn';
 import MiniButton from '@/components/ui/MiniButton';
 import TextURL from '@/components/ui/TextURL';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import useWindowSize from '@/hooks/useWindowSize';
 import { ILibraryItem, LibraryItemType } from '@/models/library';
 import { useFitHeight } from '@/stores/appLayout';
diff --git a/rsconcept/frontend/src/pages/LibraryPage/ToolbarSearch.tsx b/rsconcept/frontend/src/pages/LibraryPage/ToolbarSearch.tsx
index 13a632f5..41be5fa3 100644
--- a/rsconcept/frontend/src/pages/LibraryPage/ToolbarSearch.tsx
+++ b/rsconcept/frontend/src/pages/LibraryPage/ToolbarSearch.tsx
@@ -78,7 +78,7 @@ function ToolbarSearch({ total, filtered }: ToolbarSearchProps) {
   return (
     <div
       className={clsx(
-        'sticky top-0', // prettier: split lines
+        'sticky top-0', //
         'h-[2.2rem]',
         'flex items-center gap-3',
         'border-b',
diff --git a/rsconcept/frontend/src/pages/LibraryPage/ViewSideLocation.tsx b/rsconcept/frontend/src/pages/LibraryPage/ViewSideLocation.tsx
index 0b4dbe1b..d28e8011 100644
--- a/rsconcept/frontend/src/pages/LibraryPage/ViewSideLocation.tsx
+++ b/rsconcept/frontend/src/pages/LibraryPage/ViewSideLocation.tsx
@@ -2,15 +2,15 @@ import clsx from 'clsx';
 import { toast } from 'react-toastify';
 
 import { useAuth } from '@/backend/auth/useAuth';
+import { useLibrary } from '@/backend/library/useLibrary';
 import { SubfoldersIcon } from '@/components/DomainIcons';
 import { IconFolderEdit, IconFolderTree } from '@/components/Icons';
 import BadgeHelp from '@/components/info/BadgeHelp';
 import { CProps } from '@/components/props';
 import SelectLocation from '@/components/select/SelectLocation';
 import MiniButton from '@/components/ui/MiniButton';
-import { useLibrary } from '@/context/LibraryContext';
 import useWindowSize from '@/hooks/useWindowSize';
-import { FolderNode, FolderTree } from '@/models/FolderTree';
+import { FolderNode } from '@/models/FolderTree';
 import { HelpTopic } from '@/models/miscellaneous';
 import { useFitHeight } from '@/stores/appLayout';
 import { useLibrarySearchStore } from '@/stores/librarySearch';
@@ -18,12 +18,11 @@ import { PARAMETER, prefixes } from '@/utils/constants';
 import { information } from '@/utils/labels';
 
 interface ViewSideLocationProps {
-  folderTree: FolderTree;
   isVisible: boolean;
   onRenameLocation: () => void;
 }
 
-function ViewSideLocation({ folderTree, isVisible, onRenameLocation }: ViewSideLocationProps) {
+function ViewSideLocation({ isVisible, onRenameLocation }: ViewSideLocationProps) {
   const { user } = useAuth();
   const { items } = useLibrary();
   const windowSize = useWindowSize();
@@ -104,7 +103,6 @@ function ViewSideLocation({ folderTree, isVisible, onRenameLocation }: ViewSideL
       </div>
       <SelectLocation
         value={location}
-        folderTree={folderTree}
         prefix={prefixes.folders_list}
         onClick={handleClickFolder}
         style={{ maxHeight: maxHeight }}
diff --git a/rsconcept/frontend/src/pages/LoginPage.tsx b/rsconcept/frontend/src/pages/LoginPage.tsx
index c79e2b7e..3a2024c6 100644
--- a/rsconcept/frontend/src/pages/LoginPage.tsx
+++ b/rsconcept/frontend/src/pages/LoginPage.tsx
@@ -12,7 +12,7 @@ import SubmitButton from '@/components/ui/SubmitButton';
 import TextInput from '@/components/ui/TextInput';
 import TextURL from '@/components/ui/TextURL';
 import ExpectedAnonymous from '@/components/wrap/ExpectedAnonymous';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import useQueryStrings from '@/hooks/useQueryStrings';
 import { resources } from '@/utils/constants';
 
diff --git a/rsconcept/frontend/src/pages/ManualsPage/ManualsPage.tsx b/rsconcept/frontend/src/pages/ManualsPage/ManualsPage.tsx
index e0119635..366b57a9 100644
--- a/rsconcept/frontend/src/pages/ManualsPage/ManualsPage.tsx
+++ b/rsconcept/frontend/src/pages/ManualsPage/ManualsPage.tsx
@@ -3,7 +3,7 @@
 import { useCallback } from 'react';
 
 import { urls } from '@/app/urls';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import useQueryStrings from '@/hooks/useQueryStrings';
 import { HelpTopic } from '@/models/miscellaneous';
 import { useMainHeight } from '@/stores/appLayout';
diff --git a/rsconcept/frontend/src/dialogs/DlgChangeLocation.tsx b/rsconcept/frontend/src/pages/OssPage/DlgChangeLocation.tsx
similarity index 90%
rename from rsconcept/frontend/src/dialogs/DlgChangeLocation.tsx
rename to rsconcept/frontend/src/pages/OssPage/DlgChangeLocation.tsx
index 20b621f9..fda2dcd4 100644
--- a/rsconcept/frontend/src/dialogs/DlgChangeLocation.tsx
+++ b/rsconcept/frontend/src/pages/OssPage/DlgChangeLocation.tsx
@@ -9,7 +9,6 @@ import SelectLocationHead from '@/components/select/SelectLocationHead';
 import Label from '@/components/ui/Label';
 import Modal from '@/components/ui/Modal';
 import TextArea from '@/components/ui/TextArea';
-import { useLibrary } from '@/context/LibraryContext';
 import { LocationHead } from '@/models/library';
 import { combineLocation, validateLocation } from '@/models/libraryAPI';
 import { useDialogsStore } from '@/stores/dialogs';
@@ -26,8 +25,6 @@ function DlgChangeLocation() {
   const [head, setHead] = useState<LocationHead>(initial.substring(0, 2) as LocationHead);
   const [body, setBody] = useState<string>(initial.substring(3));
 
-  const { folders } = useLibrary();
-
   const location = combineLocation(head, body);
   const isValid = initial !== location && validateLocation(location);
 
@@ -54,12 +51,7 @@ function DlgChangeLocation() {
           excluded={!user?.is_staff ? [LocationHead.LIBRARY] : []}
         />
       </div>
-      <SelectLocationContext
-        folderTree={folders}
-        value={location}
-        onChange={handleSelectLocation}
-        className='max-h-[9.2rem]'
-      />
+      <SelectLocationContext value={location} onChange={handleSelectLocation} className='max-h-[9.2rem]' />
       <TextArea id='dlg_cst_body' label='Путь' rows={3} value={body} onChange={event => setBody(event.target.value)} />
     </Modal>
   );
diff --git a/rsconcept/frontend/src/pages/OssPage/EditorOssCard/EditorOssCard.tsx b/rsconcept/frontend/src/pages/OssPage/EditorOssCard/EditorOssCard.tsx
index 3f2c35db..1f7679a9 100644
--- a/rsconcept/frontend/src/pages/OssPage/EditorOssCard/EditorOssCard.tsx
+++ b/rsconcept/frontend/src/pages/OssPage/EditorOssCard/EditorOssCard.tsx
@@ -3,7 +3,6 @@
 import clsx from 'clsx';
 
 import FlexColumn from '@/components/ui/FlexColumn';
-import { useOSS } from '@/context/OssContext';
 import EditorLibraryItem from '@/pages/RSFormPage/EditorRSFormCard/EditorLibraryItem';
 import ToolbarRSFormCard from '@/pages/RSFormPage/EditorRSFormCard/ToolbarRSFormCard';
 import { globals } from '@/utils/constants';
@@ -19,7 +18,6 @@ interface EditorOssCardProps {
 }
 
 function EditorOssCard({ isModified, onDestroy, setIsModified }: EditorOssCardProps) {
-  const { schema } = useOSS();
   const controller = useOssEdit();
 
   function initiateSubmit() {
@@ -57,10 +55,10 @@ function EditorOssCard({ isModified, onDestroy, setIsModified }: EditorOssCardPr
       >
         <FlexColumn className='px-3'>
           <FormOSS id={globals.library_item_editor} isModified={isModified} setIsModified={setIsModified} />
-          <EditorLibraryItem item={schema} isModified={isModified} controller={controller} />
+          <EditorLibraryItem item={controller.schema} isModified={isModified} controller={controller} />
         </FlexColumn>
 
-        {schema ? <OssStats stats={schema.stats} /> : null}
+        {controller.schema ? <OssStats stats={controller.schema.stats} /> : null}
       </div>
     </>
   );
diff --git a/rsconcept/frontend/src/pages/OssPage/EditorOssCard/FormOSS.tsx b/rsconcept/frontend/src/pages/OssPage/EditorOssCard/FormOSS.tsx
index c38ce776..032ce23e 100644
--- a/rsconcept/frontend/src/pages/OssPage/EditorOssCard/FormOSS.tsx
+++ b/rsconcept/frontend/src/pages/OssPage/EditorOssCard/FormOSS.tsx
@@ -4,12 +4,13 @@ import clsx from 'clsx';
 import { useEffect, useState } from 'react';
 import { toast } from 'react-toastify';
 
+import { ILibraryUpdateDTO } from '@/backend/library/api';
+import { useUpdateItem } from '@/backend/library/useUpdateItem';
 import { IconSave } from '@/components/Icons';
 import SubmitButton from '@/components/ui/SubmitButton';
 import TextArea from '@/components/ui/TextArea';
 import TextInput from '@/components/ui/TextInput';
-import { useOSS } from '@/context/OssContext';
-import { ILibraryUpdateData, LibraryItemType } from '@/models/library';
+import { LibraryItemType } from '@/models/library';
 import ToolbarItemAccess from '@/pages/RSFormPage/EditorRSFormCard/ToolbarItemAccess';
 import { information } from '@/utils/labels';
 
@@ -22,8 +23,9 @@ interface FormOSSProps {
 }
 
 function FormOSS({ id, isModified, setIsModified }: FormOSSProps) {
-  const { schema, update, processing } = useOSS();
+  const { updateItem: update } = useUpdateItem();
   const controller = useOssEdit();
+  const schema = controller.schema;
 
   const [title, setTitle] = useState(schema?.title ?? '');
   const [alias, setAlias] = useState(schema?.alias ?? '');
@@ -73,7 +75,11 @@ function FormOSS({ id, isModified, setIsModified }: FormOSSProps) {
     if (event) {
       event.preventDefault();
     }
-    const data: ILibraryUpdateData = {
+    if (!schema) {
+      return;
+    }
+    const data: ILibraryUpdateDTO = {
+      id: schema.id,
       item_type: LibraryItemType.RSFORM,
       title: title,
       alias: alias,
@@ -126,7 +132,7 @@ function FormOSS({ id, isModified, setIsModified }: FormOSSProps) {
         <SubmitButton
           text='Сохранить изменения'
           className='self-center mt-4'
-          loading={processing}
+          loading={controller.isProcessing}
           disabled={!isModified}
           icon={<IconSave size='1.25rem' />}
         />
diff --git a/rsconcept/frontend/src/pages/OssPage/EditorOssGraph/OssFlow.tsx b/rsconcept/frontend/src/pages/OssPage/EditorOssGraph/OssFlow.tsx
index a03dd412..029c74bd 100644
--- a/rsconcept/frontend/src/pages/OssPage/EditorOssGraph/OssFlow.tsx
+++ b/rsconcept/frontend/src/pages/OssPage/EditorOssGraph/OssFlow.tsx
@@ -18,7 +18,6 @@ import {
 
 import { CProps } from '@/components/props';
 import Overlay from '@/components/ui/Overlay';
-import { useOSS } from '@/context/OssContext';
 import { OssNode } from '@/models/miscellaneous';
 import { OperationID } from '@/models/oss';
 import { useMainHeight } from '@/stores/appLayout';
@@ -42,7 +41,6 @@ interface OssFlowProps {
 
 function OssFlow({ isModified, setIsModified }: OssFlowProps) {
   const mainHeight = useMainHeight();
-  const model = useOSS();
   const controller = useOssEdit();
   const flow = useReactFlow();
 
@@ -71,12 +69,12 @@ function OssFlow({ isModified, setIsModified }: OssFlowProps) {
   });
 
   useEffect(() => {
-    if (!model.schema) {
+    if (!controller.schema) {
       setNodes([]);
       setEdges([]);
     } else {
       setNodes(
-        model.schema.items.map(operation => ({
+        controller.schema.items.map(operation => ({
           id: String(operation.id),
           data: { label: operation.alias, operation: operation },
           position: { x: operation.position_x, y: operation.position_y },
@@ -84,15 +82,15 @@ function OssFlow({ isModified, setIsModified }: OssFlowProps) {
         }))
       );
       setEdges(
-        model.schema.arguments.map((argument, index) => ({
+        controller.schema.arguments.map((argument, index) => ({
           id: String(index),
           source: String(argument.argument),
           target: String(argument.operation),
           type: edgeStraight ? 'straight' : 'simplebezier',
           animated: edgeAnimate,
           targetHandle:
-            model.schema!.operationByID.get(argument.argument)!.position_x >
-            model.schema!.operationByID.get(argument.operation)!.position_x
+            controller.schema!.operationByID.get(argument.argument)!.position_x >
+            controller.schema!.operationByID.get(argument.operation)!.position_x
               ? 'right'
               : 'left'
         }))
@@ -101,7 +99,7 @@ function OssFlow({ isModified, setIsModified }: OssFlowProps) {
     setTimeout(() => {
       setIsModified(false);
     }, PARAMETER.graphRefreshDelay);
-  }, [model.schema, setNodes, setEdges, setIsModified, toggleReset, edgeStraight, edgeAnimate]);
+  }, [controller.schema, setNodes, setEdges, setIsModified, toggleReset, edgeStraight, edgeAnimate]);
 
   function getPositions() {
     return nodes.map(node => ({
@@ -179,7 +177,7 @@ function OssFlow({ isModified, setIsModified }: OssFlowProps) {
   }
 
   function handleSaveImage() {
-    if (!model.schema) {
+    if (!controller.schema) {
       return;
     }
     const canvas: HTMLElement | null = document.querySelector('.react-flow__viewport');
@@ -204,7 +202,7 @@ function OssFlow({ isModified, setIsModified }: OssFlowProps) {
     })
       .then(dataURL => {
         const a = document.createElement('a');
-        a.setAttribute('download', `${model.schema?.alias ?? 'oss'}.png`);
+        a.setAttribute('download', `${controller.schema?.alias ?? 'oss'}.png`);
         a.setAttribute('href', dataURL);
         a.click();
       })
diff --git a/rsconcept/frontend/src/pages/OssPage/MenuOssTabs.tsx b/rsconcept/frontend/src/pages/OssPage/MenuOssTabs.tsx
index a40d349b..d68a1db3 100644
--- a/rsconcept/frontend/src/pages/OssPage/MenuOssTabs.tsx
+++ b/rsconcept/frontend/src/pages/OssPage/MenuOssTabs.tsx
@@ -1,5 +1,6 @@
 'use client';
 
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
 import {
@@ -20,8 +21,6 @@ import Button from '@/components/ui/Button';
 import Divider from '@/components/ui/Divider';
 import Dropdown from '@/components/ui/Dropdown';
 import DropdownButton from '@/components/ui/DropdownButton';
-import { useConceptNavigation } from '@/context/NavigationContext';
-import { useOSS } from '@/context/OssContext';
 import useDropdown from '@/hooks/useDropdown';
 import { UserRole } from '@/models/user';
 import { useRoleStore } from '@/stores/role';
@@ -37,7 +36,6 @@ function MenuOssTabs({ onDestroy }: MenuOssTabsProps) {
   const controller = useOssEdit();
   const router = useConceptNavigation();
   const { user } = useAuth();
-  const model = useOSS();
 
   const role = useRoleStore(state => state.role);
   const setRole = useRoleStore(state => state.setRole);
@@ -179,14 +177,14 @@ function MenuOssTabs({ onDestroy }: MenuOssTabsProps) {
               text={labelUserRole(UserRole.EDITOR)}
               title={describeUserRole(UserRole.EDITOR)}
               icon={<IconEditor size='1rem' className='icon-primary' />}
-              disabled={!model.isOwned && !model.schema?.editors.includes(user.id)}
+              disabled={!controller.isOwned && !controller.schema?.editors.includes(user.id)}
               onClick={() => handleChangeRole(UserRole.EDITOR)}
             />
             <DropdownButton
               text={labelUserRole(UserRole.OWNER)}
               title={describeUserRole(UserRole.OWNER)}
               icon={<IconOwner size='1rem' className='icon-primary' />}
-              disabled={!model.isOwned}
+              disabled={!controller.isOwned}
               onClick={() => handleChangeRole(UserRole.OWNER)}
             />
             <DropdownButton
diff --git a/rsconcept/frontend/src/pages/OssPage/OssEditContext.tsx b/rsconcept/frontend/src/pages/OssPage/OssEditContext.tsx
index ab52702d..c3b8510d 100644
--- a/rsconcept/frontend/src/pages/OssPage/OssEditContext.tsx
+++ b/rsconcept/frontend/src/pages/OssPage/OssEditContext.tsx
@@ -3,25 +3,19 @@
 import { createContext, useCallback, useContext, useEffect, useState } from 'react';
 import { toast } from 'react-toastify';
 
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
-import { useLibrary } from '@/context/LibraryContext';
-import { useConceptNavigation } from '@/context/NavigationContext';
-import { useOSS } from '@/context/OssContext';
+import { useLibrary } from '@/backend/library/useLibrary';
+import { useSetAccessPolicy } from '@/backend/library/useSetAccessPolicy';
+import { useSetEditors } from '@/backend/library/useSetEditors';
+import { useSetLocation } from '@/backend/library/useSetLocation';
+import { useSetOwner } from '@/backend/library/useSetOwner';
+import { useOssSuspense } from '@/backend/oss/useOSS';
 import { AccessPolicy, ILibraryItemEditor, LibraryItemID } from '@/models/library';
 import { Position2D } from '@/models/miscellaneous';
 import { calculateInsertPosition } from '@/models/miscellaneousAPI';
-import {
-  ICstRelocateData,
-  IOperationCreateData,
-  IOperationDeleteData,
-  IOperationPosition,
-  IOperationSchema,
-  IOperationSetInputData,
-  IOperationUpdateData,
-  OperationID,
-  OperationType
-} from '@/models/oss';
+import { IOperationPosition, IOperationSchema, OperationID, OperationType } from '@/models/oss';
 import { UserID, UserRole } from '@/models/user';
 import { useDialogsStore } from '@/stores/dialogs';
 import { usePreferencesStore } from '@/stores/preferences';
@@ -43,6 +37,7 @@ export interface IOssEditContext extends ILibraryItemEditor {
   schema?: IOperationSchema;
   selected: OperationID[];
 
+  isOwned: boolean;
   isMutable: boolean;
   isProcessing: boolean;
   isAttachedToOSS: boolean;
@@ -82,19 +77,32 @@ export const useOssEdit = () => {
 };
 
 interface OssEditStateProps {
+  itemID: LibraryItemID;
   selected: OperationID[];
   setSelected: React.Dispatch<React.SetStateAction<OperationID[]>>;
 }
 
-export const OssEditState = ({ selected, setSelected, children }: React.PropsWithChildren<OssEditStateProps>) => {
+export const OssEditState = ({
+  itemID,
+  selected,
+  setSelected,
+  children
+}: React.PropsWithChildren<OssEditStateProps>) => {
   const router = useConceptNavigation();
   const { user } = useAuth();
+  const { items: libraryItems } = useLibrary();
   const adminMode = usePreferencesStore(state => state.adminMode);
 
   const role = useRoleStore(state => state.role);
   const adjustRole = useRoleStore(state => state.adjustRole);
-  const model = useOSS();
-  const library = useLibrary();
+  const model = useOssSuspense({ itemID: itemID });
+
+  const { setOwner: setItemOwner } = useSetOwner();
+  const { setLocation: setItemLocation } = useSetLocation();
+  const { setAccessPolicy: setItemAccessPolicy } = useSetAccessPolicy();
+  const { setEditors: setItemEditors } = useSetEditors();
+
+  const isOwned = user?.id === model.schema?.owner || false;
 
   const isMutable = role > UserRole.READER && !model.schema?.read_only;
 
@@ -124,15 +132,8 @@ export const OssEditState = ({ selected, setSelected, children }: React.PropsWit
     [model.schema, adjustRole, model.isOwned, user, adminMode]
   );
 
-  const handleSetLocation = useCallback(
-    (newLocation: string) => {
-      if (!model.schema) {
-        return;
-      }
-      model.setLocation(newLocation, () => toast.success(information.moveComplete));
-    },
-    [model]
-  );
+  const handleSetLocation = (newLocation: string) =>
+    setItemLocation({ itemID: model.itemID!, location: newLocation }, () => toast.success(information.moveComplete));
 
   const share = useCallback(() => {
     const currentRef = window.location.href;
@@ -143,26 +144,14 @@ export const OssEditState = ({ selected, setSelected, children }: React.PropsWit
       .catch(console.error);
   }, []);
 
-  const setOwner = useCallback(
-    (newOwner: UserID) => {
-      model.setOwner(newOwner, () => toast.success(information.changesSaved));
-    },
-    [model]
-  );
+  const setOwner = (newOwner: UserID) =>
+    setItemOwner({ itemID: model.itemID!, owner: newOwner }, () => toast.success(information.changesSaved));
 
-  const setAccessPolicy = useCallback(
-    (newPolicy: AccessPolicy) => {
-      model.setAccessPolicy(newPolicy, () => toast.success(information.changesSaved));
-    },
-    [model]
-  );
+  const setAccessPolicy = (newPolicy: AccessPolicy) =>
+    setItemAccessPolicy({ itemID: model.itemID!, policy: newPolicy }, () => toast.success(information.changesSaved));
 
-  const handleSetEditors = useCallback(
-    (newEditors: UserID[]) => {
-      model.setEditors(newEditors, () => toast.success(information.changesSaved));
-    },
-    [model]
-  );
+  const handleSetEditors = (newEditors: UserID[]) =>
+    setItemEditors({ itemID: model.itemID!, editors: newEditors }, () => toast.success(information.changesSaved));
 
   const openOperationSchema = useCallback(
     (target: OperationID) => {
@@ -197,7 +186,7 @@ export const OssEditState = ({ selected, setSelected, children }: React.PropsWit
       const target = calculateInsertPosition(
         model.schema!,
         data.item_data.operation_type,
-        data.arguments!,
+        data.arguments,
         positions,
         insertPosition
       );
@@ -258,7 +247,7 @@ export const OssEditState = ({ selected, setSelected, children }: React.PropsWit
       if (!model.schema || !operation) {
         return;
       }
-      if (library.items.find(item => item.alias === operation.alias && item.location === model.schema!.location)) {
+      if (libraryItems.find(item => item.alias === operation.alias && item.location === model.schema!.location)) {
         toast.error(errors.inputAlreadyExists);
         return;
       }
@@ -267,7 +256,7 @@ export const OssEditState = ({ selected, setSelected, children }: React.PropsWit
         router.push(urls.schema(new_schema.id));
       });
     },
-    [model, library.items, router]
+    [model, libraryItems, router]
   );
 
   const setTargetInput = useCallback(
@@ -311,19 +300,10 @@ export const OssEditState = ({ selected, setSelected, children }: React.PropsWit
     [model]
   );
 
-  const promptEditors = useCallback(() => {
-    if (!model.schema) {
-      return;
-    }
-    showEditEditors({ editors: model.schema.editors, setEditors: handleSetEditors });
-  }, [model.schema, showEditEditors, handleSetEditors]);
+  const promptEditors = () => showEditEditors({ editors: model.schema?.editors ?? [], setEditors: handleSetEditors });
 
-  const promptLocation = useCallback(() => {
-    if (!model.schema) {
-      return;
-    }
-    showEditLocation({ initial: model.schema.location, onChangeLocation: handleSetLocation });
-  }, [model.schema, showEditLocation, handleSetLocation]);
+  const promptLocation = () =>
+    showEditLocation({ initial: model.schema?.location ?? '', onChangeLocation: handleSetLocation });
 
   const promptCreateOperation = useCallback(
     ({ defaultX, defaultY, inputs, positions, callback }: ICreateOperationPrompt) => {
@@ -395,6 +375,7 @@ export const OssEditState = ({ selected, setSelected, children }: React.PropsWit
         showTooltip,
         setShowTooltip,
 
+        isOwned,
         isMutable,
         isProcessing: model.processing,
         isAttachedToOSS: false,
diff --git a/rsconcept/frontend/src/pages/OssPage/OssPage.tsx b/rsconcept/frontend/src/pages/OssPage/OssPage.tsx
index a5118e00..7375cdda 100644
--- a/rsconcept/frontend/src/pages/OssPage/OssPage.tsx
+++ b/rsconcept/frontend/src/pages/OssPage/OssPage.tsx
@@ -1,17 +1,22 @@
 'use client';
 
+import { Suspense } from 'react';
 import { useParams } from 'react-router';
 
-import { OssState } from '@/context/OssContext';
+import Loader from '@/components/ui/Loader';
+import { OssState } from '@/pages/OssPage/OssContext';
 
 import OssTabs from './OssTabs';
 
 function OssPage() {
   const params = useParams();
+  const itemID = params.id ? Number(params.id) : undefined;
   return (
-    <OssState itemID={params.id ?? ''}>
-      <OssTabs />
-    </OssState>
+    <Suspense fallback={<Loader />}>
+      <OssState itemID={itemID}>
+        <OssTabs />
+      </OssState>
+    </Suspense>
   );
 }
 
diff --git a/rsconcept/frontend/src/pages/OssPage/OssTabs.tsx b/rsconcept/frontend/src/pages/OssPage/OssTabs.tsx
index b96ae033..5f352cae 100644
--- a/rsconcept/frontend/src/pages/OssPage/OssTabs.tsx
+++ b/rsconcept/frontend/src/pages/OssPage/OssTabs.tsx
@@ -6,16 +6,15 @@ import { useEffect, useState } from 'react';
 import { TabList, TabPanel, Tabs } from 'react-tabs';
 import { toast } from 'react-toastify';
 
+import { useBlockNavigation, useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
+import { useDeleteItem } from '@/backend/library/useDeleteItem';
 import InfoError, { ErrorData } from '@/components/info/InfoError';
 import Loader from '@/components/ui/Loader';
 import Overlay from '@/components/ui/Overlay';
 import TabLabel from '@/components/ui/TabLabel';
 import TextURL from '@/components/ui/TextURL';
-import { useLibrary } from '@/context/LibraryContext';
-import { useBlockNavigation, useConceptNavigation } from '@/context/NavigationContext';
-import { useOSS } from '@/context/OssContext';
 import useQueryStrings from '@/hooks/useQueryStrings';
 import { OperationID } from '@/models/oss';
 import { useAppLayoutStore } from '@/stores/appLayout';
@@ -36,10 +35,10 @@ function OssTabs() {
   const query = useQueryStrings();
   const activeTab = query.get('tab') ? (Number(query.get('tab')) as OssTabID) : OssTabID.GRAPH;
   const { user } = useAuth();
+  const { deleteItem } = useDeleteItem();
 
   const hideFooter = useAppLayoutStore(state => state.hideFooter);
-  const { schema, loading, loadingError: errorLoading } = useOSS();
-  const { destroyItem } = useLibrary();
+  const { schema, loading, loadingError: errorLoading } = useOSSControl();
 
   const [isModified, setIsModified] = useState(false);
   const [selected, setSelected] = useState<OperationID[]>([]);
@@ -98,7 +97,7 @@ function OssTabs() {
     if (!schema || !window.confirm(prompts.deleteOSS)) {
       return;
     }
-    destroyItem(schema.id, () => {
+    deleteItem(schema.id, () => {
       toast.success(information.itemDestroyed);
       router.push(urls.library);
     });
@@ -128,7 +127,7 @@ function OssTabs() {
           <div className='overflow-x-hidden'>
             <TabPanel>
               <EditorRSForm
-                isModified={isModified} // prettier: split lines
+                isModified={isModified} //
                 setIsModified={setIsModified}
                 onDestroy={onDestroySchema}
               />
diff --git a/rsconcept/frontend/src/pages/PasswordChangePage.tsx b/rsconcept/frontend/src/pages/PasswordChangePage.tsx
index 5c4c2e5a..12db2eb4 100644
--- a/rsconcept/frontend/src/pages/PasswordChangePage.tsx
+++ b/rsconcept/frontend/src/pages/PasswordChangePage.tsx
@@ -11,7 +11,7 @@ import InfoError, { ErrorData } from '@/components/info/InfoError';
 import SubmitButton from '@/components/ui/SubmitButton';
 import TextInput from '@/components/ui/TextInput';
 import DataLoader from '@/components/wrap/DataLoader';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import useQueryStrings from '@/hooks/useQueryStrings';
 
 function PasswordChangePage() {
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorConstituenta/ControlsOverlay.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorConstituenta/ControlsOverlay.tsx
index 45bcb38f..50d94c71 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorConstituenta/ControlsOverlay.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorConstituenta/ControlsOverlay.tsx
@@ -30,7 +30,7 @@ function ControlsOverlay({ constituenta, disabled, modified, processing, onRenam
       ) : null}
       <div
         className={clsx(
-          'pt-1 sm:pl-[1.375rem] pl-1', // prettier: split lines
+          'pt-1 sm:pl-[1.375rem] pl-1', //
           'text-sm font-medium whitespace-nowrap',
           'select-text cursor-default',
           disabled && !processing && 'pl-[1.6rem] sm:pl-[2.8rem]'
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorConstituenta/FormConstituenta.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorConstituenta/FormConstituenta.tsx
index 5ef8b9d3..ed25b866 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorConstituenta/FormConstituenta.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorConstituenta/FormConstituenta.tsx
@@ -4,6 +4,8 @@ import clsx from 'clsx';
 import { useEffect, useLayoutEffect, useState } from 'react';
 import { toast } from 'react-toastify';
 
+import { ICstUpdateDTO } from '@/backend/rsform/api';
+import { useCstUpdate } from '@/backend/rsform/useCstUpdate';
 import { IconChild, IconPredecessor, IconSave } from '@/components/Icons';
 import { CProps } from '@/components/props';
 import RefsInput from '@/components/RefsInput';
@@ -11,14 +13,14 @@ import Indicator from '@/components/ui/Indicator';
 import Overlay from '@/components/ui/Overlay';
 import SubmitButton from '@/components/ui/SubmitButton';
 import TextArea from '@/components/ui/TextArea';
-import { useRSForm } from '@/context/RSFormContext';
-import { ConstituentaID, CstType, IConstituenta, ICstUpdateData } from '@/models/rsform';
+import { ConstituentaID, CstType, IConstituenta } from '@/models/rsform';
 import { isBaseSet, isBasicConcept, isFunctional } from '@/models/rsformAPI';
 import { IExpressionParse, ParsingStatus } from '@/models/rslang';
 import { useDialogsStore } from '@/stores/dialogs';
 import { errors, information, labelCstTypification } from '@/utils/labels';
 
 import EditorRSExpression from '../EditorRSExpression';
+import { useRSEdit } from '../RSEditContext';
 import ControlsOverlay from './ControlsOverlay';
 
 interface FormConstituentaProps {
@@ -49,7 +51,9 @@ function FormConstituenta({
   onEditTerm,
   onOpenEdit
 }: FormConstituentaProps) {
-  const { schema, cstUpdate, processing } = useRSForm();
+  const { cstUpdate } = useCstUpdate();
+  const controller = useRSEdit();
+  const schema = controller.schema;
 
   const [term, setTerm] = useState(state?.term_raw ?? '');
   const [textDefinition, setTextDefinition] = useState(state?.definition_raw ?? '');
@@ -114,26 +118,19 @@ function FormConstituenta({
     if (event) {
       event.preventDefault();
     }
-    if (!state || processing) {
+    if (!state || controller.isProcessing || !schema) {
       return;
     }
-    const data: ICstUpdateData = {
+    const data: ICstUpdateDTO = {
       target: state.id,
-      item_data: {}
+      item_data: {
+        term_raw: state.term_raw !== term ? term : undefined,
+        definition_formal: state.definition_formal !== expression ? expression : undefined,
+        definition_raw: state.definition_raw !== textDefinition ? textDefinition : undefined,
+        convention: state.convention !== convention ? convention : undefined
+      }
     };
-    if (state.term_raw !== term) {
-      data.item_data.term_raw = term;
-    }
-    if (state.definition_formal !== expression) {
-      data.item_data.definition_formal = expression;
-    }
-    if (state.definition_raw !== textDefinition) {
-      data.item_data.definition_raw = textDefinition;
-    }
-    if (state.convention !== convention) {
-      data.item_data.convention = convention;
-    }
-    cstUpdate(data, () => toast.success(information.changesSaved));
+    cstUpdate({ itemID: schema.id, data }, () => toast.success(information.changesSaved));
   }
 
   function handleTypeGraph(event: CProps.EventMouse) {
@@ -152,7 +149,7 @@ function FormConstituenta({
         <ControlsOverlay
           disabled={disabled}
           modified={isModified}
-          processing={processing}
+          processing={controller.isProcessing}
           constituenta={state}
           onEditTerm={onEditTerm}
           onRename={onRename}
@@ -244,7 +241,7 @@ function FormConstituenta({
               />
             ) : null}
 
-            {!showConvention && (!disabled || processing) ? (
+            {!showConvention && (!disabled || controller.isProcessing) ? (
               <button
                 key='cst_disable_comment'
                 id='cst_disable_comment'
@@ -257,7 +254,7 @@ function FormConstituenta({
               </button>
             ) : null}
 
-            {!disabled || processing ? (
+            {!disabled || controller.isProcessing ? (
               <div className='mx-auto flex'>
                 <SubmitButton
                   key='cst_form_submit'
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression/EditorRSExpression.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression/EditorRSExpression.tsx
index 873942d1..6cb63d9e 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression/EditorRSExpression.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression/EditorRSExpression.tsx
@@ -10,8 +10,7 @@ import RSInput from '@/components/RSInput';
 import { parser as rslangParser } from '@/components/RSInput/rslang/parserAST';
 import { RSTextWrapper } from '@/components/RSInput/textEditing';
 import Overlay from '@/components/ui/Overlay';
-import { useRSForm } from '@/context/RSFormContext';
-import useCheckConstituenta from '@/hooks/useCheckConstituenta';
+import useRSParse from '@/hooks/useRSParse';
 import { HelpTopic } from '@/models/miscellaneous';
 import { ConstituentaID, IConstituenta } from '@/models/rsform';
 import { getDefinitionPrefix } from '@/models/rsformAPI';
@@ -22,6 +21,7 @@ import { usePreferencesStore } from '@/stores/preferences';
 import { transformAST } from '@/utils/codemirror';
 import { errors, labelTypification } from '@/utils/labels';
 
+import { useRSEdit } from '../RSEditContext';
 import ParsingResult from './ParsingResult';
 import RSEditorControls from './RSEditControls';
 import StatusBar from './StatusBar';
@@ -56,11 +56,10 @@ function EditorRSExpression({
   onShowTypeGraph,
   ...restProps
 }: EditorRSExpressionProps) {
-  const model = useRSForm();
+  const controller = useRSEdit();
 
   const [isModified, setIsModified] = useState(false);
-  const parser = useCheckConstituenta({ schema: model.schema });
-  const { resetParse } = parser;
+  const parser = useRSParse({ schema: controller.schema });
   const rsInput = useRef<ReactCodeMirrorRef>(null);
 
   const showControls = usePreferencesStore(state => state.showExpressionControls);
@@ -68,8 +67,8 @@ function EditorRSExpression({
 
   useEffect(() => {
     setIsModified(false);
-    resetParse();
-  }, [activeCst, resetParse, toggleReset]);
+    parser.resetParse();
+  }, [activeCst, parser, toggleReset]);
 
   function handleChange(newValue: string) {
     onChangeExpression(newValue);
@@ -151,7 +150,7 @@ function EditorRSExpression({
         className='w-fit pl-[8.5rem] xs:pl-[2rem] flex gap-1'
       >
         <StatusBar
-          processing={parser.processing}
+          processing={parser.isPending}
           isModified={isModified}
           activeCst={activeCst}
           parseData={parser.parseData}
@@ -168,13 +167,13 @@ function EditorRSExpression({
         disabled={disabled}
         onChange={handleChange}
         onAnalyze={handleCheckExpression}
-        schema={model.schema}
+        schema={controller.schema}
         onOpenEdit={onOpenEdit}
         {...restProps}
       />
 
       <RSEditorControls
-        isOpen={showControls && (!disabled || (model.processing && !activeCst.is_inherited))}
+        isOpen={showControls && (!disabled || (controller.isProcessing && !activeCst.is_inherited))}
         disabled={disabled}
         onEdit={handleEdit}
       />
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression/ToolbarRSExpression.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression/ToolbarRSExpression.tsx
index 24de0b31..de463193 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression/ToolbarRSExpression.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorRSExpression/ToolbarRSExpression.tsx
@@ -1,8 +1,8 @@
+import { useIsProcessingRSForm } from '@/backend/rsform/useIsProcessingRSForm';
 import { IconControls, IconTree, IconTypeGraph } from '@/components/Icons';
 import { CProps } from '@/components/props';
 import MiniButton from '@/components/ui/MiniButton';
 import Overlay from '@/components/ui/Overlay';
-import { useRSForm } from '@/context/RSFormContext';
 import { usePreferencesStore } from '@/stores/preferences';
 
 interface ToolbarRSExpressionProps {
@@ -12,13 +12,13 @@ interface ToolbarRSExpressionProps {
 }
 
 function ToolbarRSExpression({ disabled, showTypeGraph, showAST }: ToolbarRSExpressionProps) {
-  const model = useRSForm();
+  const isProcessing = useIsProcessingRSForm();
   const showControls = usePreferencesStore(state => state.showExpressionControls);
   const toggleControls = usePreferencesStore(state => state.toggleShowExpressionControls);
 
   return (
     <Overlay position='top-[-0.5rem] right-0' layer='z-pop' className='cc-icons'>
-      {!disabled || model.processing ? (
+      {!disabled || isProcessing ? (
         <MiniButton
           title='Отображение специальной клавиатуры'
           icon={<IconControls size='1.25rem' className={showControls ? 'icon-primary' : ''} />}
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/EditorLibraryItem.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/EditorLibraryItem.tsx
index 0fd38723..78ab5975 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/EditorLibraryItem.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/EditorLibraryItem.tsx
@@ -1,6 +1,7 @@
 import { Suspense, useCallback } from 'react';
 import { useIntl } from 'react-intl';
 
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { urls } from '@/app/urls';
 import { useLabelUser } from '@/backend/users/useLabelUser';
 import {
@@ -19,7 +20,6 @@ import MiniButton from '@/components/ui/MiniButton';
 import Overlay from '@/components/ui/Overlay';
 import Tooltip from '@/components/ui/Tooltip';
 import ValueIcon from '@/components/ui/ValueIcon';
-import { useConceptNavigation } from '@/context/NavigationContext';
 import useDropdown from '@/hooks/useDropdown';
 import { ILibraryItemData, ILibraryItemEditor } from '@/models/library';
 import { UserID, UserRole } from '@/models/user';
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/EditorRSFormCard.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/EditorRSFormCard.tsx
index eb2fdd2d..032c6798 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/EditorRSFormCard.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/EditorRSFormCard.tsx
@@ -3,7 +3,6 @@
 import clsx from 'clsx';
 
 import FlexColumn from '@/components/ui/FlexColumn';
-import { useRSForm } from '@/context/RSFormContext';
 import { globals } from '@/utils/constants';
 
 import { useRSEdit } from '../RSEditContext';
@@ -19,7 +18,6 @@ interface EditorRSFormCardProps {
 }
 
 function EditorRSFormCard({ isModified, onDestroy, setIsModified }: EditorRSFormCardProps) {
-  const model = useRSForm();
   const controller = useRSEdit();
 
   function initiateSubmit() {
@@ -56,10 +54,10 @@ function EditorRSFormCard({ isModified, onDestroy, setIsModified }: EditorRSForm
       >
         <FlexColumn className='flex-shrink'>
           <FormRSForm id={globals.library_item_editor} isModified={isModified} setIsModified={setIsModified} />
-          <EditorLibraryItem item={model.schema} isModified={isModified} controller={controller} />
+          <EditorLibraryItem item={controller.schema} isModified={isModified} controller={controller} />
         </FlexColumn>
 
-        {model.schema ? <RSFormStats stats={model.schema.stats} isArchive={model.isArchive} /> : null}
+        {controller.schema ? <RSFormStats stats={controller.schema.stats} isArchive={controller.isArchive} /> : null}
       </div>
     </>
   );
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/FormRSForm.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/FormRSForm.tsx
index f2382121..c1152436 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/FormRSForm.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorRSFormCard/FormRSForm.tsx
@@ -3,13 +3,15 @@
 import clsx from 'clsx';
 import { useEffect, useState } from 'react';
 
+import { ILibraryUpdateDTO } from '@/backend/library/api';
+import { useUpdateItem } from '@/backend/library/useUpdateItem';
 import { IconSave } from '@/components/Icons';
 import SelectVersion from '@/components/select/SelectVersion';
 import Label from '@/components/ui/Label';
 import SubmitButton from '@/components/ui/SubmitButton';
 import TextArea from '@/components/ui/TextArea';
 import TextInput from '@/components/ui/TextInput';
-import { ILibraryUpdateData, LibraryItemType } from '@/models/library';
+import { LibraryItemType } from '@/models/library';
 
 import { useRSEdit } from '../RSEditContext';
 import ToolbarItemAccess from './ToolbarItemAccess';
@@ -24,6 +26,7 @@ interface FormRSFormProps {
 function FormRSForm({ id, isModified, setIsModified }: FormRSFormProps) {
   const controller = useRSEdit();
   const schema = controller.schema;
+  const { updateItem: update } = useUpdateItem();
 
   const [title, setTitle] = useState(schema?.title ?? '');
   const [alias, setAlias] = useState(schema?.alias ?? '');
@@ -73,7 +76,11 @@ function FormRSForm({ id, isModified, setIsModified }: FormRSFormProps) {
     if (event) {
       event.preventDefault();
     }
-    const data: ILibraryUpdateData = {
+    if (!schema) {
+      return;
+    }
+    const data: ILibraryUpdateDTO = {
+      id: schema.id,
       item_type: LibraryItemType.RSFORM,
       title: title,
       alias: alias,
@@ -81,7 +88,7 @@ function FormRSForm({ id, isModified, setIsModified }: FormRSFormProps) {
       visible: visible,
       read_only: readOnly
     };
-    controller.updateSchema(data);
+    update(data);
   };
 
   return (
@@ -118,7 +125,7 @@ function FormRSForm({ id, isModified, setIsModified }: FormRSFormProps) {
           <SelectVersion
             id='schema_version'
             className='select-none'
-            value={schema?.version} // prettier: split lines
+            value={schema?.version} //
             items={schema?.versions}
             onSelectValue={controller.viewVersion}
           />
diff --git a/rsconcept/frontend/src/pages/RSFormPage/EditorTermGraph/SchemasGuide.tsx b/rsconcept/frontend/src/pages/RSFormPage/EditorTermGraph/SchemasGuide.tsx
index 9a2ae762..d9b86411 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/EditorTermGraph/SchemasGuide.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/EditorTermGraph/SchemasGuide.tsx
@@ -1,6 +1,6 @@
+import { useLibrary } from '@/backend/library/useLibrary';
 import { IconHelp } from '@/components/Icons';
 import Tooltip from '@/components/ui/Tooltip';
-import { useLibrary } from '@/context/LibraryContext';
 import { LibraryItemID } from '@/models/library';
 import { IRSForm } from '@/models/rsform';
 import { colorBgSchemas } from '@/styling/color';
@@ -11,7 +11,7 @@ interface SchemasGuideProps {
 }
 
 function SchemasGuide({ schema }: SchemasGuideProps) {
-  const library = useLibrary();
+  const { items: libraryItems } = useLibrary();
 
   const schemas = (() => {
     const processed = new Set<LibraryItemID>();
@@ -19,7 +19,7 @@ function SchemasGuide({ schema }: SchemasGuideProps) {
     const indexes: number[] = [];
     schema.items.forEach(cst => {
       if (cst.parent_schema && !processed.has(cst.parent_schema)) {
-        const item = library.items.find(item => item.id === cst.parent_schema);
+        const item = libraryItems.find(item => item.id === cst.parent_schema);
         if (item) {
           aliases.push(item.alias);
         } else {
diff --git a/rsconcept/frontend/src/pages/RSFormPage/MenuRSTabs.tsx b/rsconcept/frontend/src/pages/RSFormPage/MenuRSTabs.tsx
index cb754c13..04e674e9 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/MenuRSTabs.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/MenuRSTabs.tsx
@@ -1,5 +1,7 @@
 'use client';
 
+import { useGlobalOss } from '@/app/GlobalOssContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
 import {
@@ -32,9 +34,6 @@ import Button from '@/components/ui/Button';
 import Divider from '@/components/ui/Divider';
 import Dropdown from '@/components/ui/Dropdown';
 import DropdownButton from '@/components/ui/DropdownButton';
-import { useGlobalOss } from '@/context/GlobalOssContext';
-import { useConceptNavigation } from '@/context/NavigationContext';
-import { useRSForm } from '@/context/RSFormContext';
 import useDropdown from '@/hooks/useDropdown';
 import { AccessPolicy } from '@/models/library';
 import { UserRole } from '@/models/user';
@@ -52,7 +51,6 @@ function MenuRSTabs({ onDestroy }: MenuRSTabsProps) {
   const controller = useRSEdit();
   const router = useConceptNavigation();
   const { user } = useAuth();
-  const model = useRSForm();
   const oss = useGlobalOss();
 
   const role = useRoleStore(state => state.role);
@@ -172,7 +170,7 @@ function MenuRSTabs({ onDestroy }: MenuRSTabsProps) {
             <DropdownButton
               text='Клонировать'
               icon={<IconClone size='1rem' className='icon-green' />}
-              disabled={model.isArchive}
+              disabled={controller.isArchive}
               onClick={handleClone}
             />
           ) : null}
@@ -228,7 +226,7 @@ function MenuRSTabs({ onDestroy }: MenuRSTabsProps) {
         </Dropdown>
       </div>
 
-      {!model.isArchive && user ? (
+      {!controller.isArchive && user ? (
         <div ref={editMenu.ref}>
           <Button
             dense
@@ -290,7 +288,7 @@ function MenuRSTabs({ onDestroy }: MenuRSTabsProps) {
           </Dropdown>
         </div>
       ) : null}
-      {model.isArchive && user ? (
+      {controller.isArchive && user ? (
         <Button
           dense
           noBorder
@@ -338,14 +336,14 @@ function MenuRSTabs({ onDestroy }: MenuRSTabsProps) {
               text={labelAccessMode(UserRole.EDITOR)}
               title={describeAccessMode(UserRole.EDITOR)}
               icon={<IconEditor size='1rem' className='icon-primary' />}
-              disabled={!model.isOwned && !model.schema?.editors.includes(user.id)}
+              disabled={!controller.isOwned && !controller.schema?.editors.includes(user.id)}
               onClick={() => handleChangeMode(UserRole.EDITOR)}
             />
             <DropdownButton
               text={labelAccessMode(UserRole.OWNER)}
               title={describeAccessMode(UserRole.OWNER)}
               icon={<IconOwner size='1rem' className='icon-primary' />}
-              disabled={!model.isOwned}
+              disabled={!controller.isOwned}
               onClick={() => handleChangeMode(UserRole.OWNER)}
             />
             <DropdownButton
diff --git a/rsconcept/frontend/src/pages/RSFormPage/RSEditContext.tsx b/rsconcept/frontend/src/pages/RSFormPage/RSEditContext.tsx
index 8e8adbc8..30f2ef0f 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/RSEditContext.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/RSEditContext.tsx
@@ -1,37 +1,41 @@
 'use client';
 
 import fileDownload from 'js-file-download';
-import { createContext, useCallback, useContext, useEffect, useMemo, useState } from 'react';
+import { createContext, useContext, useEffect, useState } from 'react';
 import { toast } from 'react-toastify';
 
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { urls } from '@/app/urls';
 import { useAuth } from '@/backend/auth/useAuth';
-import { useConceptNavigation } from '@/context/NavigationContext';
-import { useRSForm } from '@/context/RSFormContext';
+import { useSetAccessPolicy } from '@/backend/library/useSetAccessPolicy';
+import { useSetEditors } from '@/backend/library/useSetEditors';
+import { useSetLocation } from '@/backend/library/useSetLocation';
+import { useSetOwner } from '@/backend/library/useSetOwner';
+import { useFindPredecessor } from '@/backend/oss/useFindPredecessor';
+import { ICstCreateDTO, ICstRenameDTO, ICstUpdateDTO, IInlineSynthesisDTO } from '@/backend/rsform/api';
+import { useCstCreate } from '@/backend/rsform/useCstCreate';
+import { useCstDelete } from '@/backend/rsform/useCstDelete';
+import { useCstMove } from '@/backend/rsform/useCstMove';
+import { useCstRename } from '@/backend/rsform/useCstRename';
+import { useCstSubstitute } from '@/backend/rsform/useCstSubstitute';
+import { useCstUpdate } from '@/backend/rsform/useCstUpdate';
+import { useDownloadRSForm } from '@/backend/rsform/useDownloadRSForm';
+import { useInlineSynthesis } from '@/backend/rsform/useInlineSynthesis';
+import { useIsProcessingRSForm } from '@/backend/rsform/useIsProcessingRSForm';
+import { useProduceStructure } from '@/backend/rsform/useProduceStructure';
+import { useResetAliases } from '@/backend/rsform/useResetAliases';
+import { useRestoreOrder } from '@/backend/rsform/useRestoreOrder';
+import { useRSFormSuspense } from '@/backend/rsform/useRSForm';
 import {
   AccessPolicy,
   ILibraryItemEditor,
-  ILibraryUpdateData,
   IVersionData,
   LibraryItemID,
   LocationHead,
   VersionID
 } from '@/models/library';
-import { ICstSubstituteData } from '@/models/oss';
-import {
-  ConstituentaID,
-  CstType,
-  IConstituenta,
-  IConstituentaMeta,
-  ICstCreateData,
-  ICstMovetoData,
-  ICstRenameData,
-  ICstUpdateData,
-  IInlineSynthesisData,
-  IRSForm,
-  ITargetCst,
-  TermForm
-} from '@/models/rsform';
+import { ICstSubstitutions } from '@/models/oss';
+import { ConstituentaID, CstType, IConstituenta, IConstituentaMeta, IRSForm, TermForm } from '@/models/rsform';
 import { generateAlias } from '@/models/rsformAPI';
 import { UserID, UserRole } from '@/models/user';
 import { useDialogsStore } from '@/stores/dialogs';
@@ -47,6 +51,8 @@ export interface IRSEditContext extends ILibraryItemEditor {
   schema?: IRSForm;
   selected: ConstituentaID[];
 
+  isOwned: boolean;
+  isArchive: boolean;
   isMutable: boolean;
   isContentEditable: boolean;
   isProcessing: boolean;
@@ -54,8 +60,6 @@ export interface IRSEditContext extends ILibraryItemEditor {
   canProduceStructure: boolean;
   canDeleteSelected: boolean;
 
-  updateSchema: (data: ILibraryUpdateData) => void;
-
   setOwner: (newOwner: UserID) => void;
   setAccessPolicy: (newPolicy: AccessPolicy) => void;
   promptEditors: () => void;
@@ -108,6 +112,9 @@ export const useRSEdit = () => {
 };
 
 interface RSEditStateProps {
+  itemID: LibraryItemID;
+  versionID?: VersionID;
+
   selected: ConstituentaID[];
   isModified: boolean;
   setSelected: React.Dispatch<React.SetStateAction<ConstituentaID[]>>;
@@ -118,6 +125,8 @@ interface RSEditStateProps {
 }
 
 export const RSEditState = ({
+  itemID,
+  versionID,
   selected,
   setSelected,
   activeCst,
@@ -131,23 +140,41 @@ export const RSEditState = ({
   const adminMode = usePreferencesStore(state => state.adminMode);
   const role = useRoleStore(state => state.role);
   const adjustRole = useRoleStore(state => state.adjustRole);
-  const model = useRSForm();
 
-  const isMutable = useMemo(() => role > UserRole.READER && !model.schema?.read_only, [role, model.schema?.read_only]);
-  const isContentEditable = useMemo(() => isMutable && !model.isArchive, [isMutable, model.isArchive]);
-  const canDeleteSelected = useMemo(
-    () => selected.length > 0 && selected.every(id => !model.schema?.cstByID.get(id)?.is_inherited),
-    [selected, model.schema]
-  );
-  const isAttachedToOSS = useMemo(
-    () =>
-      !!model.schema &&
-      model.schema.oss.length > 0 &&
-      (model.schema.stats.count_inherited > 0 || model.schema.items.length === 0),
-    [model.schema]
-  );
+  const { schema } = useRSFormSuspense({ itemID: itemID, version: versionID });
+  const isProcessing = useIsProcessingRSForm();
 
-  const [renameInitialData, setRenameInitialData] = useState<ICstRenameData>();
+  const { download: downloadFile } = useDownloadRSForm();
+  const { findPredecessor } = useFindPredecessor();
+
+  const { setOwner: setItemOwner } = useSetOwner();
+  const { setLocation: setItemLocation } = useSetLocation();
+  const { setAccessPolicy: setItemAccessPolicy } = useSetAccessPolicy();
+  const { setEditors: setItemEditors } = useSetEditors();
+
+  const { cstCreate } = useCstCreate();
+  const { cstRename } = useCstRename();
+  const { cstSubstitute } = useCstSubstitute();
+  const { cstMove } = useCstMove();
+  const { cstDelete } = useCstDelete();
+  const { cstUpdate } = useCstUpdate();
+
+  const { produceStructure: produceStructureInternal } = useProduceStructure();
+  const { inlineSynthesis: inlineSynthesisInternal } = useInlineSynthesis();
+  const { restoreOrder: restoreOrderInternal } = useRestoreOrder();
+  const { resetAliases: resetAliasesInternal } = useResetAliases();
+
+  const isOwned = user?.id === schema?.owner || false;
+
+  const isArchive = !!versionID;
+
+  const isMutable = role > UserRole.READER && !schema?.read_only;
+  const isContentEditable = isMutable && !isArchive;
+  const canDeleteSelected = selected.length > 0 && selected.every(id => !schema?.cstByID.get(id)?.is_inherited);
+  const isAttachedToOSS =
+    !!schema && schema.oss.length > 0 && (schema.stats.count_inherited > 0 || schema.items.length === 0);
+
+  const [renameInitialData, setRenameInitialData] = useState<ICstRenameDTO>();
 
   const showClone = useDialogsStore(state => state.showCloneLibraryItem);
   const showCreateVersion = useDialogsStore(state => state.showCreateVersion);
@@ -168,241 +195,200 @@ export const RSEditState = ({
   const showUpload = useDialogsStore(state => state.showUploadRSForm);
   const showQR = useDialogsStore(state => state.showQR);
 
-  const typeInfo = useMemo(
-    () =>
-      model.schema
-        ? model.schema.items.map(item => ({
-            alias: item.alias,
-            result: item.parse.typification,
-            args: item.parse.args
-          }))
-        : [],
-    [model.schema]
-  );
+  const typeInfo = schema
+    ? schema.items.map(item => ({
+        alias: item.alias,
+        result: item.parse.typification,
+        args: item.parse.args
+      }))
+    : [];
+
+  const canProduceStructure =
+    !!activeCst &&
+    !!activeCst.parse.typification &&
+    activeCst.cst_type !== CstType.BASE &&
+    activeCst.cst_type !== CstType.CONSTANT;
 
   useEffect(
     () =>
       adjustRole({
-        isOwner: model.isOwned,
-        isEditor: (user && model.schema?.editors.includes(user?.id)) ?? false,
+        isOwner: isOwned,
+        isEditor: (user && schema?.editors.includes(user?.id)) ?? false,
         isStaff: user?.is_staff ?? false,
         adminMode: adminMode
       }),
-    [model.schema, adjustRole, model.isOwned, user, adminMode]
+    [schema, adjustRole, isOwned, user, adminMode]
   );
 
-  const updateSchema = useCallback(
-    (data: ILibraryUpdateData) => model.update(data, () => toast.success(information.changesSaved)),
-    [model]
-  );
+  function viewVersion(version?: VersionID, newTab?: boolean) {
+    router.push(urls.schema(itemID, version), newTab);
+  }
 
-  const viewVersion = useCallback(
-    (version?: VersionID, newTab?: boolean) => router.push(urls.schema(model.itemID, version), newTab),
-    [router, model]
-  );
+  function viewPredecessor(target: ConstituentaID) {
+    findPredecessor({ target: target }, reference =>
+      router.push(
+        urls.schema_props({
+          id: reference.schema,
+          active: reference.id,
+          tab: RSTabID.CST_EDIT
+        })
+      )
+    );
+  }
 
-  const viewPredecessor = useCallback(
-    (target: ConstituentaID) =>
-      model.findPredecessor({ target: target }, reference =>
-        router.push(
-          urls.schema_props({
-            id: reference.schema,
-            active: reference.id,
-            tab: RSTabID.CST_EDIT
-          })
-        )
-      ),
-    [router, model]
-  );
+  function viewOSS(target: LibraryItemID, newTab?: boolean) {
+    router.push(urls.oss(target), newTab);
+  }
 
-  const viewOSS = useCallback(
-    (target: LibraryItemID, newTab?: boolean) => router.push(urls.oss(target), newTab),
-    [router]
-  );
-
-  const restoreVersion = useCallback(() => {
-    if (!model.versionID || !window.confirm(prompts.restoreArchive)) {
+  function restoreVersion() {
+    if (!versionID || !window.confirm(prompts.restoreArchive)) {
       return;
     }
-    model.versionRestore(model.versionID, () => {
+    model.versionRestore(versionID, () => {
       toast.success(information.versionRestored);
       viewVersion(undefined);
     });
-  }, [model, viewVersion]);
+  }
 
-  const calculateCloneLocation = useCallback(() => {
-    if (!model.schema) {
+  function calculateCloneLocation() {
+    if (!schema) {
       return LocationHead.USER;
     }
-    const location = model.schema.location;
-    const head = model.schema.location.substring(0, 2) as LocationHead;
+    const location = schema.location;
+    const head = schema.location.substring(0, 2) as LocationHead;
     if (head === LocationHead.LIBRARY) {
       return user?.is_staff ? location : LocationHead.USER;
     }
-    if (model.schema.owner === user?.id) {
+    if (schema.owner === user?.id) {
       return location;
     }
     return head === LocationHead.USER ? LocationHead.USER : location;
-  }, [model.schema, user]);
+  }
 
-  const handleCreateCst = useCallback(
-    (data: ICstCreateData) => {
-      if (!model.schema) {
-        return;
+  function handleCreateCst(data: ICstCreateDTO) {
+    if (!schema) {
+      return;
+    }
+    data.alias = data.alias || generateAlias(data.cst_type, schema);
+    cstCreate({ itemID: itemID, data }, newCst => {
+      toast.success(information.newConstituent(newCst.alias));
+      setSelected([newCst.id]);
+      if (onCreateCst) onCreateCst(newCst);
+    });
+  }
+
+  function handleRenameCst(data: ICstRenameDTO) {
+    const oldAlias = renameInitialData?.alias ?? '';
+    cstRename({ itemID: itemID, data }, () => toast.success(information.renameComplete(oldAlias, data.alias)));
+  }
+
+  function handleSubstituteCst(data: ICstSubstitutions) {
+    cstSubstitute({ itemID: itemID, data }, () => {
+      setSelected(prev => prev.filter(id => !data.substitutions.find(sub => sub.original === id)));
+      toast.success(information.substituteSingle);
+    });
+  }
+
+  function handleDeleteCst(deleted: ConstituentaID[]) {
+    if (!schema) {
+      return;
+    }
+    const data = {
+      items: deleted
+    };
+
+    const deletedNames = deleted.map(id => schema.cstByID.get(id)!.alias).join(', ');
+    const isEmpty = deleted.length === schema.items.length;
+    const nextActive = isEmpty ? undefined : getNextActiveOnDelete(activeCst?.id, schema.items, deleted);
+
+    cstDelete({ itemID: itemID, data }, () => {
+      toast.success(information.constituentsDestroyed(deletedNames));
+      setSelected(nextActive ? [nextActive] : []);
+      onDeleteCst?.(nextActive);
+    });
+  }
+
+  function handleSaveWordforms(forms: TermForm[]) {
+    if (!activeCst) {
+      return;
+    }
+    const data: ICstUpdateDTO = {
+      target: activeCst.id,
+      item_data: { term_forms: forms }
+    };
+    cstUpdate({ itemID: itemID, data }, () => toast.success(information.changesSaved));
+  }
+
+  function handleCreateVersion(data: IVersionData) {
+    if (!schema) {
+      return;
+    }
+    model.versionCreate(data, () => {
+      toast.success(information.newVersion(data.version));
+    });
+  }
+
+  function handleDeleteVersion(versionID: VersionID) {
+    if (!schema) {
+      return;
+    }
+    model.versionDelete(versionID, () => {
+      toast.success(information.versionDestroyed);
+      if (versionID === versionID) {
+        viewVersion(undefined);
       }
-      data.alias = data.alias || generateAlias(data.cst_type, model.schema);
-      model.cstCreate(data, newCst => {
-        toast.success(information.newConstituent(newCst.alias));
-        setSelected([newCst.id]);
-        if (onCreateCst) onCreateCst(newCst);
-      });
-    },
-    [model, setSelected, onCreateCst]
-  );
+    });
+  }
 
-  const handleRenameCst = useCallback(
-    (data: ICstRenameData) => {
-      const oldAlias = renameInitialData?.alias ?? '';
-      model.cstRename(data, () => toast.success(information.renameComplete(oldAlias, data.alias)));
-    },
-    [model, renameInitialData]
-  );
+  function handleUpdateVersion(versionID: VersionID, data: IVersionData) {
+    if (!schema) {
+      return;
+    }
+    model.versionUpdate(versionID, data, () => toast.success(information.changesSaved));
+  }
 
-  const handleSubstituteCst = useCallback(
-    (data: ICstSubstituteData) => {
-      model.cstSubstitute(data, () => {
-        setSelected(prev => prev.filter(id => !data.substitutions.find(sub => sub.original === id)));
-        toast.success(information.substituteSingle);
-      });
-    },
-    [model, setSelected]
-  );
+  const handleSetLocation = (newLocation: string) =>
+    setItemLocation({ itemID: itemID, location: newLocation }, () => toast.success(information.moveComplete));
 
-  const handleDeleteCst = useCallback(
-    (deleted: ConstituentaID[]) => {
-      if (!model.schema) {
-        return;
-      }
-      const data = {
-        items: deleted
-      };
+  function handleInlineSynthesis(data: IInlineSynthesisDTO) {
+    if (!schema) {
+      return;
+    }
+    const oldCount = schema.items.length;
+    inlineSynthesisInternal({ itemID: itemID, data }, newSchema => {
+      setSelected([]);
+      toast.success(information.addedConstituents(newSchema.items.length - oldCount));
+    });
+  }
 
-      const deletedNames = deleted.map(id => model.schema!.cstByID.get(id)!.alias).join(', ');
-      const isEmpty = deleted.length === model.schema.items.length;
-      const nextActive = isEmpty ? undefined : getNextActiveOnDelete(activeCst?.id, model.schema.items, deleted);
-
-      model.cstDelete(data, () => {
-        toast.success(information.constituentsDestroyed(deletedNames));
-        setSelected(nextActive ? [nextActive] : []);
-        onDeleteCst?.(nextActive);
-      });
-    },
-    [model, activeCst, onDeleteCst, setSelected]
-  );
-
-  const handleSaveWordforms = useCallback(
-    (forms: TermForm[]) => {
-      if (!activeCst) {
-        return;
-      }
-      const data: ICstUpdateData = {
-        target: activeCst.id,
-        item_data: { term_forms: forms }
-      };
-      model.cstUpdate(data, () => toast.success(information.changesSaved));
-    },
-    [model, activeCst]
-  );
-
-  const handleCreateVersion = useCallback(
-    (data: IVersionData) => {
-      if (!model.schema) {
-        return;
-      }
-      model.versionCreate(data, () => {
-        toast.success(information.newVersion(data.version));
-      });
-    },
-    [model]
-  );
-
-  const handleDeleteVersion = useCallback(
-    (versionID: VersionID) => {
-      if (!model.schema) {
-        return;
-      }
-      model.versionDelete(versionID, () => {
-        toast.success(information.versionDestroyed);
-        if (String(versionID) === model.versionID) {
-          viewVersion(undefined);
-        }
-      });
-    },
-    [model, viewVersion]
-  );
-
-  const handleUpdateVersion = useCallback(
-    (versionID: VersionID, data: IVersionData) => {
-      if (!model.schema) {
-        return;
-      }
-      model.versionUpdate(versionID, data, () => toast.success(information.changesSaved));
-    },
-    [model]
-  );
-
-  const handleSetLocation = useCallback(
-    (newLocation: string) => {
-      if (!model.schema) {
-        return;
-      }
-      model.setLocation(newLocation, () => toast.success(information.moveComplete));
-    },
-    [model]
-  );
-
-  const handleInlineSynthesis = useCallback(
-    (data: IInlineSynthesisData) => {
-      if (!model.schema) {
-        return;
-      }
-      const oldCount = model.schema.items.length;
-      model.inlineSynthesis(data, newSchema => {
-        setSelected([]);
-        toast.success(information.addedConstituents(newSchema.items.length - oldCount));
-      });
-    },
-    [model, setSelected]
-  );
-
-  const createVersion = useCallback(() => {
-    if (!model.schema || (isModified && !promptUnsaved())) {
+  function createVersion() {
+    if (!schema || (isModified && !promptUnsaved())) {
       return;
     }
     showCreateVersion({
-      versions: model.schema.versions,
+      versions: schema.versions,
       onCreate: handleCreateVersion,
       selected: selected,
-      totalCount: model.schema.items.length
+      totalCount: schema.items.length
     });
-  }, [isModified, model.schema, selected, handleCreateVersion, showCreateVersion]);
+  }
 
-  const promptEditVersions = useCallback(() => {
-    if (!model.schema) {
+  function promptEditVersions() {
+    if (!schema) {
       return;
     }
     showEditVersions({
-      versions: model.schema.versions,
+      versions: schema.versions,
       onDelete: handleDeleteVersion,
       onUpdate: handleUpdateVersion
     });
-  }, [model.schema, handleDeleteVersion, handleUpdateVersion, showEditVersions]);
+  }
 
-  const moveUp = useCallback(() => {
-    if (!model.schema?.items || selected.length === 0) {
+  function moveUp() {
+    if (!schema?.items || selected.length === 0) {
       return;
     }
-    const currentIndex = model.schema.items.reduce((prev, cst, index) => {
+    const currentIndex = schema.items.reduce((prev, cst, index) => {
       if (!selected.includes(cst.id)) {
         return prev;
       } else if (prev === -1) {
@@ -411,19 +397,21 @@ export const RSEditState = ({
       return Math.min(prev, index);
     }, -1);
     const target = Math.max(0, currentIndex - 1);
-    const data: ICstMovetoData = {
-      items: selected,
-      move_to: target
-    };
-    model.cstMoveTo(data);
-  }, [model, selected]);
+    cstMove({
+      itemID: itemID,
+      data: {
+        items: selected,
+        move_to: target
+      }
+    });
+  }
 
-  const moveDown = useCallback(() => {
-    if (!model.schema?.items || selected.length === 0) {
+  function moveDown() {
+    if (!schema?.items || selected.length === 0) {
       return;
     }
     let count = 0;
-    const currentIndex = model.schema.items.reduce((prev, cst, index) => {
+    const currentIndex = schema.items.reduce((prev, cst, index) => {
       if (!selected.includes(cst.id)) {
         return prev;
       } else {
@@ -434,47 +422,46 @@ export const RSEditState = ({
         return Math.max(prev, index);
       }
     }, -1);
-    const target = Math.min(model.schema.items.length - 1, currentIndex - count + 2);
-    const data: ICstMovetoData = {
-      items: selected,
-      move_to: target
-    };
-    model.cstMoveTo(data);
-  }, [model, selected]);
-
-  const createCst = useCallback(
-    (type: CstType | undefined, skipDialog: boolean, definition?: string) => {
-      if (!model.schema) {
-        return;
+    const target = Math.min(schema.items.length - 1, currentIndex - count + 2);
+    cstMove({
+      itemID: itemID,
+      data: {
+        items: selected,
+        move_to: target
       }
-      const targetType = type ?? activeCst?.cst_type ?? CstType.BASE;
-      const data: ICstCreateData = {
-        insert_after: activeCst?.id ?? null,
-        cst_type: targetType,
-        alias: generateAlias(targetType, model.schema),
-        term_raw: '',
-        definition_formal: definition ?? '',
-        definition_raw: '',
-        convention: '',
-        term_forms: []
-      };
-      if (skipDialog) {
-        handleCreateCst(data);
-      } else {
-        showCreateCst({ schema: model.schema, onCreate: handleCreateCst, initial: data });
-      }
-    },
-    [activeCst, handleCreateCst, model.schema, showCreateCst]
-  );
+    });
+  }
 
-  const cloneCst = useCallback(() => {
-    if (!activeCst || !model.schema) {
+  function createCst(type: CstType | undefined, skipDialog: boolean, definition?: string) {
+    if (!schema) {
       return;
     }
-    const data: ICstCreateData = {
+    const targetType = type ?? activeCst?.cst_type ?? CstType.BASE;
+    const data: ICstCreateDTO = {
+      insert_after: activeCst?.id ?? null,
+      cst_type: targetType,
+      alias: generateAlias(targetType, schema),
+      term_raw: '',
+      definition_formal: definition ?? '',
+      definition_raw: '',
+      convention: '',
+      term_forms: []
+    };
+    if (skipDialog) {
+      handleCreateCst(data);
+    } else {
+      showCreateCst({ schema: schema, onCreate: handleCreateCst, initial: data });
+    }
+  }
+
+  function cloneCst() {
+    if (!activeCst || !schema) {
+      return;
+    }
+    const data: ICstCreateDTO = {
       insert_after: activeCst.id,
       cst_type: activeCst.cst_type,
-      alias: generateAlias(activeCst.cst_type, model.schema),
+      alias: generateAlias(activeCst.cst_type, schema),
       term_raw: activeCst.term_raw,
       definition_formal: activeCst.definition_formal,
       definition_raw: activeCst.definition_raw,
@@ -482,48 +469,48 @@ export const RSEditState = ({
       term_forms: activeCst.term_forms
     };
     handleCreateCst(data);
-  }, [activeCst, handleCreateCst, model.schema]);
+  }
 
-  const renameCst = useCallback(() => {
-    if (!activeCst || !model.schema) {
+  function renameCst() {
+    if (!activeCst || !schema) {
       return;
     }
-    const data: ICstRenameData = {
+    const data: ICstRenameDTO = {
       target: activeCst.id,
       alias: activeCst.alias,
       cst_type: activeCst.cst_type
     };
     setRenameInitialData(data);
     showRenameCst({
-      schema: model.schema,
+      schema: schema,
       initial: data,
       allowChangeType: !activeCst.is_inherited,
       onRename: handleRenameCst
     });
-  }, [activeCst, model.schema, handleRenameCst, showRenameCst]);
+  }
 
-  const substitute = useCallback(() => {
-    if (!model.schema || (isModified && !promptUnsaved())) {
+  function substitute() {
+    if (!schema || (isModified && !promptUnsaved())) {
       return;
     }
-    showSubstituteCst({ schema: model.schema, onSubstitute: handleSubstituteCst });
-  }, [isModified, model.schema, handleSubstituteCst, showSubstituteCst]);
+    showSubstituteCst({ schema: schema, onSubstitute: handleSubstituteCst });
+  }
 
-  const inlineSynthesis = useCallback(() => {
-    if (!model.schema || (isModified && !promptUnsaved())) {
+  function inlineSynthesis() {
+    if (!schema || (isModified && !promptUnsaved())) {
       return;
     }
-    showInlineSynthesis({ receiver: model.schema, onInlineSynthesis: handleInlineSynthesis });
-  }, [isModified, model.schema, handleInlineSynthesis, showInlineSynthesis]);
+    showInlineSynthesis({ receiver: schema, onInlineSynthesis: handleInlineSynthesis });
+  }
 
-  const promptDeleteCst = useCallback(() => {
-    if (!model.schema) {
+  function promptDeleteCst() {
+    if (!schema) {
       return;
     }
-    showDeleteCst({ schema: model.schema, selected: selected, onDelete: handleDeleteCst });
-  }, [model.schema, selected, handleDeleteCst, showDeleteCst]);
+    showDeleteCst({ schema: schema, selected: selected, onDelete: handleDeleteCst });
+  }
 
-  const editTermForms = useCallback(() => {
+  function editTermForms() {
     if (!activeCst) {
       return;
     }
@@ -531,114 +518,104 @@ export const RSEditState = ({
       return;
     }
     showEditTerm({ target: activeCst, onSave: handleSaveWordforms });
-  }, [isModified, activeCst, handleSaveWordforms, showEditTerm]);
+  }
 
-  const reindex = useCallback(() => model.resetAliases(() => toast.success(information.reindexComplete)), [model]);
-  const reorder = useCallback(() => model.restoreOrder(() => toast.success(information.reorderComplete)), [model]);
+  function reindex() {
+    if (!itemID) {
+      return;
+    }
+    resetAliasesInternal(itemID, () => toast.success(information.reindexComplete));
+  }
 
-  const canProduceStructure = useMemo(() => {
-    return (
-      !!activeCst &&
-      !!activeCst.parse.typification &&
-      activeCst.cst_type !== CstType.BASE &&
-      activeCst.cst_type !== CstType.CONSTANT
-    );
-  }, [activeCst]);
+  function reorder() {
+    if (!itemID) {
+      return;
+    }
+    restoreOrderInternal(itemID, () => toast.success(information.reorderComplete));
+  }
 
-  const produceStructure = useCallback(() => {
+  function produceStructure() {
     if (!activeCst) {
       return;
     }
     if (isModified && !promptUnsaved()) {
       return;
     }
-    const data: ITargetCst = {
-      target: activeCst.id
-    };
-    model.produceStructure(data, cstList => {
+    produceStructureInternal({ itemID: itemID, data: { target: activeCst.id } }, cstList => {
       toast.success(information.addedConstituents(cstList.length));
       if (cstList.length !== 0) {
         setSelected(cstList);
       }
     });
-  }, [activeCst, setSelected, model, isModified]);
+  }
 
-  const setEditors = useCallback(
-    (newEditors: UserID[]) => {
-      model.setEditors(newEditors, () => toast.success(information.changesSaved));
-    },
-    [model]
-  );
+  function handleSetEditors(newEditors: UserID[]) {
+    setItemEditors({ itemID: itemID, editors: newEditors }, () => toast.success(information.changesSaved));
+  }
 
-  const promptTemplate = useCallback(() => {
-    if ((isModified && !promptUnsaved()) || !model.schema) {
+  function promptTemplate() {
+    if ((isModified && !promptUnsaved()) || !schema) {
       return;
     }
-    showCstTemplate({ schema: model.schema, onCreate: handleCreateCst, insertAfter: activeCst?.id });
-  }, [activeCst, isModified, handleCreateCst, model.schema, showCstTemplate]);
+    showCstTemplate({ schema: schema, onCreate: handleCreateCst, insertAfter: activeCst?.id });
+  }
 
-  const promptClone = useCallback(() => {
-    if (!model.schema || (isModified && !promptUnsaved())) {
+  function promptClone() {
+    if (!schema || (isModified && !promptUnsaved())) {
       return;
     }
     showClone({
-      base: model.schema,
+      base: schema,
       initialLocation: calculateCloneLocation(),
       selected: selected,
-      totalCount: model.schema.items.length
+      totalCount: schema.items.length
     });
-  }, [isModified, model.schema, selected, showClone, calculateCloneLocation]);
+  }
 
-  const promptEditors = useCallback(() => {
-    if (!model.schema) {
+  function promptEditors() {
+    if (!schema) {
       return;
     }
-    showEditEditors({ editors: model.schema.editors, setEditors: setEditors });
-  }, [model.schema, showEditEditors, setEditors]);
+    showEditEditors({ editors: schema.editors, setEditors: handleSetEditors });
+  }
 
-  const promptLocation = useCallback(() => {
-    if (!model.schema) {
+  function promptLocation() {
+    if (!schema) {
       return;
     }
-    showEditLocation({ initial: model.schema.location, onChangeLocation: handleSetLocation });
-  }, [model.schema, showEditLocation, handleSetLocation]);
+    showEditLocation({ initial: schema.location, onChangeLocation: handleSetLocation });
+  }
 
-  const download = useCallback(() => {
-    if (isModified && !promptUnsaved()) {
+  function download() {
+    if ((isModified && !promptUnsaved()) || !schema) {
       return;
     }
-    const fileName = (model.schema?.alias ?? 'Schema') + EXTEOR_TRS_FILE;
-    model.download((data: Blob) => {
+    const fileName = (schema.alias ?? 'Schema') + EXTEOR_TRS_FILE;
+    downloadFile({ itemID: itemID, version: versionID }, (data: Blob) => {
       try {
         fileDownload(data, fileName);
       } catch (error) {
         console.error(error);
       }
     });
-  }, [model, isModified]);
+  }
 
-  const share = useCallback(() => {
+  function share() {
     const currentRef = window.location.href;
     const url = currentRef.includes('?') ? currentRef + '&share' : currentRef + '?share';
     navigator.clipboard
       .writeText(url)
       .then(() => toast.success(information.linkReady))
       .catch(console.error);
-  }, []);
+  }
 
-  const setOwner = useCallback(
-    (newOwner: UserID) => {
-      model.setOwner(newOwner, () => toast.success(information.changesSaved));
-    },
-    [model]
-  );
+  function setOwner(newOwner: UserID) {
+    setItemOwner({ itemID: itemID, owner: newOwner }, () => toast.success(information.changesSaved));
+  }
 
-  const setAccessPolicy = useCallback(
-    (newPolicy: AccessPolicy) => {
-      model.setAccessPolicy(newPolicy, () => toast.success(information.changesSaved));
-    },
-    [model]
-  );
+  function setAccessPolicy(newPolicy: AccessPolicy) {
+    setItemAccessPolicy({ itemID: itemID, policy: newPolicy }, () => toast.success(information.changesSaved));
+  }
 
   function generateQR(): string {
     const currentRef = window.location.href;
@@ -648,12 +625,14 @@ export const RSEditState = ({
   return (
     <RSEditContext
       value={{
-        schema: model.schema,
-        updateSchema,
+        schema: schema,
         selected,
+
+        isOwned,
+        isArchive,
         isMutable,
         isContentEditable,
-        isProcessing: model.processing,
+        isProcessing,
         isAttachedToOSS,
         canProduceStructure,
         canDeleteSelected,
@@ -687,7 +666,7 @@ export const RSEditState = ({
 
         promptTemplate,
         promptClone,
-        promptUpload: () => showUpload({ upload: model.upload }),
+        promptUpload: () => showUpload({ itemID: model.itemID! }),
         download,
         share,
 
diff --git a/rsconcept/frontend/src/pages/RSFormPage/RSTabs.tsx b/rsconcept/frontend/src/pages/RSFormPage/RSTabs.tsx
index 83d8e587..0b6844c4 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/RSTabs.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/RSTabs.tsx
@@ -3,21 +3,22 @@
 import axios from 'axios';
 import clsx from 'clsx';
 import { useEffect, useState } from 'react';
+import { useParams } from 'react-router';
 import { TabList, TabPanel, Tabs } from 'react-tabs';
 import { toast } from 'react-toastify';
 
+import { useGlobalOss } from '@/app/GlobalOssContext';
+import { useBlockNavigation, useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { urls } from '@/app/urls';
+import { useDeleteItem } from '@/backend/library/useDeleteItem';
 import InfoError, { ErrorData } from '@/components/info/InfoError';
 import Divider from '@/components/ui/Divider';
 import Loader from '@/components/ui/Loader';
 import Overlay from '@/components/ui/Overlay';
 import TabLabel from '@/components/ui/TabLabel';
 import TextURL from '@/components/ui/TextURL';
-import { useGlobalOss } from '@/context/GlobalOssContext';
-import { useLibrary } from '@/context/LibraryContext';
-import { useBlockNavigation, useConceptNavigation } from '@/context/NavigationContext';
-import { useRSForm } from '@/context/RSFormContext';
 import useQueryStrings from '@/hooks/useQueryStrings';
+import { LibraryItemID } from '@/models/library';
 import { ConstituentaID, IConstituenta, IConstituentaMeta } from '@/models/rsform';
 import { useAppLayoutStore } from '@/stores/appLayout';
 import { PARAMETER, prefixes } from '@/utils/constants';
@@ -39,15 +40,17 @@ export enum RSTabID {
 }
 
 function RSTabs() {
+  const params = useParams();
   const router = useConceptNavigation();
   const query = useQueryStrings();
   const activeTab = query.get('tab') ? (Number(query.get('tab')) as RSTabID) : RSTabID.CARD;
+  const itemID = params.id ? Number(params.id) : undefined;
   const version = query.get('v') ? Number(query.get('v')) : undefined;
   const cstQuery = query.get('active');
 
   const hideFooter = useAppLayoutStore(state => state.hideFooter);
-  const { schema, loading, errorLoading, isArchive, itemID } = useRSForm();
-  const library = useLibrary();
+  const { schema, loading, errorLoading, isArchive } = useRSFormControl();
+  const { deleteItem } = useDeleteItem();
   const oss = useGlobalOss();
 
   const [isModified, setIsModified] = useState(false);
@@ -166,11 +169,13 @@ function RSTabs() {
       return;
     }
     const backToOSS = oss.schema?.schemas.includes(schema.id);
-    library.destroyItem(schema.id, () => {
+    deleteItem(schema.id, () => {
       toast.success(information.itemDestroyed);
       if (backToOSS) {
-        oss.invalidate();
-        router.push(urls.oss(oss.schema!.id, OssTabID.GRAPH));
+        oss
+          .invalidate()
+          .then(() => router.push(urls.oss(oss.schema!.id, OssTabID.GRAPH)))
+          .catch(console.error);
       } else {
         router.push(urls.library);
       }
@@ -217,7 +222,7 @@ function RSTabs() {
           <div className='overflow-x-hidden'>
             <TabPanel>
               <EditorRSForm
-                isModified={isModified} // prettier: split lines
+                isModified={isModified} //
                 setIsModified={setIsModified}
                 onDestroy={onDestroySchema}
               />
@@ -256,7 +261,7 @@ function ProcessError({
 }: {
   error: ErrorData;
   isArchive: boolean;
-  itemID: string;
+  itemID?: LibraryItemID;
 }): React.ReactElement {
   if (axios.isAxiosError(error) && error.response) {
     if (error.response.status === 404) {
diff --git a/rsconcept/frontend/src/pages/RSFormPage/index.tsx b/rsconcept/frontend/src/pages/RSFormPage/index.tsx
index aa0dd14e..c67a6e2d 100644
--- a/rsconcept/frontend/src/pages/RSFormPage/index.tsx
+++ b/rsconcept/frontend/src/pages/RSFormPage/index.tsx
@@ -1 +1 @@
-export { default } from './RSFormPage';
+export { default } from './RSTabs';
diff --git a/rsconcept/frontend/src/pages/RegisterPage/FormSignup.tsx b/rsconcept/frontend/src/pages/RegisterPage/FormSignup.tsx
index 1e0cc1d1..7ca6745b 100644
--- a/rsconcept/frontend/src/pages/RegisterPage/FormSignup.tsx
+++ b/rsconcept/frontend/src/pages/RegisterPage/FormSignup.tsx
@@ -18,7 +18,7 @@ import SubmitButton from '@/components/ui/SubmitButton';
 import TextInput from '@/components/ui/TextInput';
 import TextURL from '@/components/ui/TextURL';
 import Tooltip from '@/components/ui/Tooltip';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { HelpTopic } from '@/models/miscellaneous';
 import { IUserSignupData } from '@/models/user';
 import { globals, patterns } from '@/utils/constants';
diff --git a/rsconcept/frontend/src/pages/UserProfilePage/EditorPassword.tsx b/rsconcept/frontend/src/pages/UserProfilePage/EditorPassword.tsx
index c5330aa8..b1dbed51 100644
--- a/rsconcept/frontend/src/pages/UserProfilePage/EditorPassword.tsx
+++ b/rsconcept/frontend/src/pages/UserProfilePage/EditorPassword.tsx
@@ -12,7 +12,7 @@ import InfoError, { ErrorData } from '@/components/info/InfoError';
 import FlexColumn from '@/components/ui/FlexColumn';
 import SubmitButton from '@/components/ui/SubmitButton';
 import TextInput from '@/components/ui/TextInput';
-import { useConceptNavigation } from '@/context/NavigationContext';
+import { useConceptNavigation } from '@/app/Navigation/NavigationContext';
 import { errors, information } from '@/utils/labels';
 
 function EditorPassword() {
diff --git a/rsconcept/frontend/src/pages/UserProfilePage/EditorProfile.tsx b/rsconcept/frontend/src/pages/UserProfilePage/EditorProfile.tsx
index 22a08c4b..42c50e38 100644
--- a/rsconcept/frontend/src/pages/UserProfilePage/EditorProfile.tsx
+++ b/rsconcept/frontend/src/pages/UserProfilePage/EditorProfile.tsx
@@ -10,7 +10,7 @@ import { useUpdateProfile } from '@/backend/users/useUpdateProfile';
 import InfoError, { ErrorData } from '@/components/info/InfoError';
 import SubmitButton from '@/components/ui/SubmitButton';
 import TextInput from '@/components/ui/TextInput';
-import { useBlockNavigation } from '@/context/NavigationContext';
+import { useBlockNavigation } from '@/app/Navigation/NavigationContext';
 import { information } from '@/utils/labels';
 
 function EditorProfile() {
diff --git a/rsconcept/frontend/src/stores/dialogs.ts b/rsconcept/frontend/src/stores/dialogs.ts
index c45af1db..f5966b50 100644
--- a/rsconcept/frontend/src/stores/dialogs.ts
+++ b/rsconcept/frontend/src/stores/dialogs.ts
@@ -1,7 +1,6 @@
 import { create } from 'zustand';
 
 import { DlgChangeInputSchemaProps } from '@/dialogs/DlgChangeInputSchema';
-import { DlgChangeLocationProps } from '@/dialogs/DlgChangeLocation';
 import { DlgCloneLibraryItemProps } from '@/dialogs/DlgCloneLibraryItem';
 import { DlgCreateCstProps } from '@/dialogs/DlgCreateCst/DlgCreateCst';
 import { DlgCreateOperationProps } from '@/dialogs/DlgCreateOperation/DlgCreateOperation';
@@ -24,6 +23,7 @@ import { DlgShowTypeGraphProps } from '@/dialogs/DlgShowTypeGraph/DlgShowTypeGra
 import { DlgSubstituteCstProps } from '@/dialogs/DlgSubstituteCst';
 import { DlgUploadRSFormProps } from '@/dialogs/DlgUploadRSForm';
 import { DialogType } from '@/models/miscellaneous';
+import { DlgChangeLocationProps } from '@/pages/OssPage/DlgChangeLocation';
 
 interface DialogsStore {
   active: DialogType | undefined;
diff --git a/rsconcept/frontend/src/stores/librarySearch.ts b/rsconcept/frontend/src/stores/librarySearch.ts
index 0a992997..7086578e 100644
--- a/rsconcept/frontend/src/stores/librarySearch.ts
+++ b/rsconcept/frontend/src/stores/librarySearch.ts
@@ -126,7 +126,7 @@ export function useHasCustomFilter(): boolean {
 }
 
 /** Utility function that returns the current library filter. */
-export function useLibraryFilter(): ILibraryFilter {
+export function useCreateLibraryFilter(): ILibraryFilter {
   const head = useLibrarySearchStore(state => state.head);
   const path = useLibrarySearchStore(state => state.path);
   const query = useLibrarySearchStore(state => state.query);
diff --git a/rsconcept/frontend/src/utils/codemirror.ts b/rsconcept/frontend/src/utils/codemirror.ts
index b4c98820..05520694 100644
--- a/rsconcept/frontend/src/utils/codemirror.ts
+++ b/rsconcept/frontend/src/utils/codemirror.ts
@@ -322,7 +322,7 @@ export function domTooltipEntityReference(
     const gram = document.createElement('div');
     gram.id = `tooltip-${gramStr}`;
     gram.className = clsx(
-      'min-w-[3rem]', // prettier: split lines
+      'min-w-[3rem]', //
       'px-1',
       'border rounded-md',
       'text-sm text-center whitespace-nowrap'