diff --git a/apps/chat/src/pages/api/[entitytype]/[...slug].ts b/apps/chat/src/pages/api/[entitytype]/[...slug].ts
index be0d06080b..7bbe42c5d1 100644
--- a/apps/chat/src/pages/api/[entitytype]/[...slug].ts
+++ b/apps/chat/src/pages/api/[entitytype]/[...slug].ts
@@ -2,11 +2,12 @@ import { NextApiRequest, NextApiResponse } from 'next';
 import { getServerSession } from 'next-auth';
 import { JWT, getToken } from 'next-auth/jwt';
 
+import { constructPath } from '@/src/utils/app/file';
 import { validateServerSession } from '@/src/utils/auth/session';
 import { OpenAIError } from '@/src/utils/server';
 import {
+  encodeSlugs,
   getEntityTypeFromPath,
-  getEntityUrlFromSlugs,
   isValidEntityApiType,
 } from '@/src/utils/server/api';
 import { getApiHeaders } from '@/src/utils/server/get-headers';
@@ -19,6 +20,22 @@ import { authOptions } from '@/src/pages/api/auth/[...nextauth]';
 import fetch from 'node-fetch';
 import { Readable } from 'stream';
 
+const getEntityUrlFromSlugs = (
+  dialApiHost: string,
+  req: NextApiRequest,
+): string => {
+  const entityType = getEntityTypeFromPath(req);
+  const slugs = Array.isArray(req.query.slug)
+    ? req.query.slug
+    : [req.query.slug];
+
+  if (!slugs || slugs.length === 0) {
+    throw new OpenAIError(`No ${entityType} path provided`, '', '', '400');
+  }
+
+  return constructPath(dialApiHost, 'v1', entityType, encodeSlugs(slugs));
+};
+
 const handler = async (req: NextApiRequest, res: NextApiResponse) => {
   const entityType = getEntityTypeFromPath(req);
   if (!entityType || !isValidEntityApiType(entityType)) {
diff --git a/apps/chat/src/pages/api/[entitytype]/listing.ts b/apps/chat/src/pages/api/listing/[...listing].ts
similarity index 74%
rename from apps/chat/src/pages/api/[entitytype]/listing.ts
rename to apps/chat/src/pages/api/listing/[...listing].ts
index 0f0b98113d..82c9d9dde6 100644
--- a/apps/chat/src/pages/api/[entitytype]/listing.ts
+++ b/apps/chat/src/pages/api/listing/[...listing].ts
@@ -2,14 +2,10 @@ import { NextApiRequest, NextApiResponse } from 'next';
 import { getToken } from 'next-auth/jwt';
 import { getServerSession } from 'next-auth/next';
 
+import { constructPath } from '@/src/utils/app/file';
 import { validateServerSession } from '@/src/utils/auth/session';
 import { OpenAIError } from '@/src/utils/server';
-import {
-  ApiKeys,
-  encodeApiUrl,
-  getEntityTypeFromPath,
-  isValidEntityApiType,
-} from '@/src/utils/server/api';
+import { encodeSlugs } from '@/src/utils/server/api';
 import { getApiHeaders } from '@/src/utils/server/get-headers';
 import { logger } from '@/src/utils/server/logger';
 
@@ -27,11 +23,6 @@ import { authOptions } from '@/src/pages/api/auth/[...nextauth]';
 import fetch from 'node-fetch';
 
 const handler = async (req: NextApiRequest, res: NextApiResponse) => {
-  const entityType = getEntityTypeFromPath(req);
-  if (!entityType || !isValidEntityApiType(entityType)) {
-    return res.status(400).json(errorsMessages.notValidEntityType);
-  }
-
   const session = await getServerSession(req, res, authOptions);
   const isSessionValid = validateServerSession(session, req, res);
   if (!isSessionValid) {
@@ -40,22 +31,28 @@ const handler = async (req: NextApiRequest, res: NextApiResponse) => {
 
   try {
     const {
-      path = '',
       filter,
-      bucket,
       recursive = false,
+      limit = 1000,
     } = req.query as {
-      path: string;
       filter?: BackendDataNodeType;
-      bucket: string;
       recursive?: string;
+      limit?: number;
     };
-
     const token = await getToken({ req });
+    const slugs = Array.isArray(req.query.listing)
+      ? req.query.listing
+      : [req.query.listing];
+
+    if (!slugs || slugs.length === 0) {
+      throw new OpenAIError(`No path provided`, '', '', '400');
+    }
 
-    const url = `${
-      process.env.DIAL_API_HOST
-    }/v1/metadata/${path ? `${encodeApiUrl(path)}` : `${entityType}/${bucket}`}/?limit=1000${recursive ? '&recursive=true' : ''}`;
+    const url = `${constructPath(
+      process.env.DIAL_API_HOST,
+      'v1/metadata',
+      encodeSlugs(slugs),
+    )}/?limit=${limit}&recursive=${recursive}`;
 
     const response = await fetch(url, {
       headers: getApiHeaders({ jwt: token?.access_token as string }),
@@ -78,8 +75,7 @@ const handler = async (req: NextApiRequest, res: NextApiResponse) => {
       | BackendChatFolder
     )[] = json.items || [];
 
-    const filterableEntityTypes: string[] = Object.values(ApiKeys);
-    if (filter && filterableEntityTypes.includes(entityType)) {
+    if (filter) {
       result = result.filter((item) => item.nodeType === filter);
     }
 
diff --git a/apps/chat/src/store/conversations/conversations.epics.ts b/apps/chat/src/store/conversations/conversations.epics.ts
index 537247c25c..6e3b27e3d9 100644
--- a/apps/chat/src/store/conversations/conversations.epics.ts
+++ b/apps/chat/src/store/conversations/conversations.epics.ts
@@ -132,7 +132,14 @@ const initSelectedConversationsEpic: AppEpic = (action$) =>
       return forkJoin({
         selectedConversations: zip(
           selectedIds.map((id) =>
-            ConversationService.getConversation(getConversationInfoFromId(id)),
+            ConversationService.getConversation(
+              getConversationInfoFromId(id),
+            ).pipe(
+              catchError((err) => {
+                console.error('The selected conversation was not found:', err);
+                return of(null);
+              }),
+            ),
           ),
         ),
         selectedIds: of(selectedIds),
@@ -237,10 +244,26 @@ const createNewConversationsEpic: AppEpic = (action$, state$) =>
           names: of(names),
           lastConversation:
             lastConversation && lastConversation.status !== UploadStatus.LOADED
-              ? ConversationService.getConversation(lastConversation)
+              ? ConversationService.getConversation(lastConversation).pipe(
+                  catchError((err) => {
+                    console.error(
+                      'The last used conversation was not found:',
+                      err,
+                    );
+                    return of(null);
+                  }),
+                )
               : (of(lastConversation) as Observable<Conversation>),
           conversations: shouldUploadConversationsForCompare
-            ? ConversationService.getConversations()
+            ? ConversationService.getConversations().pipe(
+                catchError((err) => {
+                  console.error(
+                    'The conversations were not upload successfully:',
+                    err,
+                  );
+                  return of([]);
+                }),
+              )
             : of(conversations),
         }),
     ),
@@ -298,7 +321,16 @@ const createNewConversationsEpic: AppEpic = (action$, state$) =>
                 }),
               ),
             ),
-            catchError(() => EMPTY),
+            catchError((err) => {
+              console.error("New conversation wasn't created:", err);
+              return of(
+                UIActions.showErrorToast(
+                  translate(
+                    'An error occurred while creating a new conversation. Most likely the conversation already exists. Please refresh the page.',
+                  ),
+                ),
+              );
+            }),
           );
         }),
       );
@@ -318,7 +350,14 @@ const createNewReplayConversationEpic: AppEpic = (action$, state$) =>
     ),
     switchMap(({ conversationAndPayload, conversations }) => {
       const { conversation } = conversationAndPayload;
-      if (!conversation) return EMPTY; // TODO: handle?
+      if (!conversation)
+        return of(
+          UIActions.showErrorToast(
+            translate(
+              'It looks like this conversation has been deleted. Please reload the page',
+            ),
+          ),
+        );
 
       const folderId = ConversationsSelectors.hasExternalParent(
         state$.value,
@@ -361,7 +400,7 @@ const createNewReplayConversationEpic: AppEpic = (action$, state$) =>
       });
 
       return of(
-        ConversationsActions.createNewConversationSuccess({
+        ConversationsActions.saveNewConversation({
           newConversation,
         }),
       );
@@ -381,7 +420,14 @@ const createNewPlaybackConversationEpic: AppEpic = (action$, state$) =>
     ),
     switchMap(({ conversationAndPayload, conversations }) => {
       const { conversation } = conversationAndPayload;
-      if (!conversation) return EMPTY; // TODO: handle?
+      if (!conversation)
+        return of(
+          UIActions.showErrorToast(
+            translate(
+              'It looks like this conversation has been deleted. Please reload the page',
+            ),
+          ),
+        );
 
       const folderId = ConversationsSelectors.hasExternalParent(
         state$.value,
@@ -421,7 +467,7 @@ const createNewPlaybackConversationEpic: AppEpic = (action$, state$) =>
       });
 
       return of(
-        ConversationsActions.createNewConversationSuccess({
+        ConversationsActions.saveNewConversation({
           newConversation,
         }),
       );
@@ -433,11 +479,19 @@ const duplicateConversationEpic: AppEpic = (action$, state$) =>
     filter(ConversationsActions.duplicateConversation.match),
     switchMap(({ payload }) =>
       forkJoin({
-        conversation: ConversationService.getConversation(payload),
+        conversationAndPayload: getOrUploadConversation(payload, state$.value),
       }),
     ),
-    switchMap(({ conversation }) => {
-      if (!conversation) return EMPTY;
+    switchMap(({ conversationAndPayload: { conversation } }) => {
+      if (!conversation) {
+        return of(
+          UIActions.showErrorToast(
+            translate(
+              'It looks like this conversation has been deleted. Please reload the page',
+            ),
+          ),
+        );
+      }
 
       const newConversation: Conversation = regenerateConversationId({
         ...conversation,
@@ -453,7 +507,7 @@ const duplicateConversationEpic: AppEpic = (action$, state$) =>
       });
 
       return of(
-        ConversationsActions.createNewConversationSuccess({
+        ConversationsActions.saveNewConversation({
           newConversation,
         }),
       );
@@ -468,14 +522,24 @@ const createNewConversationsSuccessEpic: AppEpic = (action$) =>
     ),
   );
 
-const createNewConversationSuccessEpic: AppEpic = (action$) =>
+const saveNewConversationEpic: AppEpic = (action$) =>
   action$.pipe(
-    filter((action) =>
-      ConversationsActions.createNewConversationSuccess.match(action),
-    ),
+    filter((action) => ConversationsActions.saveNewConversation.match(action)),
     switchMap(({ payload }) =>
       ConversationService.createConversation(payload.newConversation).pipe(
-        switchMap(() => EMPTY), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+        switchMap(() =>
+          of(ConversationsActions.saveNewConversationSuccess(payload)),
+        ),
+        catchError((err) => {
+          console.error(err);
+          return of(
+            UIActions.showErrorToast(
+              translate(
+                'An error occurred while saving the conversation. Most likely the conversation already exists. Please refresh the page.',
+              ),
+            ),
+          );
+        }),
       ),
     ),
   );
@@ -489,6 +553,11 @@ const deleteFolderEpic: AppEpic = (action$, state$) =>
         conversations: ConversationService.getConversations(
           payload.folderId,
           true,
+        ).pipe(
+          catchError((err) => {
+            console.error('Error during delete folder:', err);
+            return of([]);
+          }),
         ),
         folders: of(ConversationsSelectors.selectFolders(state$.value)),
       }),
@@ -617,6 +686,10 @@ const updateFolderEpic: AppEpic = (action$, state$) =>
 
           return concat(...actions);
         }),
+        catchError((err) => {
+          console.error('Error during upload conversations and folders', err);
+          return of(ConversationsActions.uploadConversationsFail());
+        }),
       );
     }),
   );
@@ -650,13 +723,7 @@ const deleteConversationsEpic: AppEpic = (action$, state$) =>
         (id) => !deleteIds.has(id),
       );
 
-      const actions: Observable<AnyAction>[] = [
-        of(
-          ConversationsActions.deleteConversationsSuccess({
-            deleteIds,
-          }),
-        ),
-      ];
+      const actions: Observable<AnyAction>[] = [];
 
       if (otherConversations.length === 0) {
         actions.push(
@@ -694,9 +761,37 @@ const deleteConversationsEpic: AppEpic = (action$, state$) =>
           Array.from(deleteIds).map((id) =>
             ConversationService.deleteConversation(
               getConversationInfoFromId(id),
+            ).pipe(
+              switchMap(() => of(null)),
+              catchError((err) => {
+                const { name } = getConversationInfoFromId(id);
+                console.error(`Error during deleting "${name}"`, err);
+                return name;
+              }),
             ),
           ),
-        ).pipe(switchMap(() => EMPTY)), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+        ).pipe(
+          switchMap((failedNames) =>
+            concat(
+              iif(
+                () => failedNames.filter(Boolean).length > 0,
+                of(
+                  UIActions.showErrorToast(
+                    translate(
+                      `An error occurred while saving the prompt(s): "${failedNames.filter(Boolean).join('", "')}"`,
+                    ),
+                  ),
+                ),
+                EMPTY,
+              ),
+              of(
+                ConversationsActions.deleteConversationsComplete({
+                  deleteIds,
+                }),
+              ),
+            ),
+          ),
+        ),
       );
     }),
   );
@@ -1363,12 +1458,7 @@ const streamMessageFailEpic: AppEpic = (action$, state$) =>
           }),
         ),
         isReplay ? of(ConversationsActions.stopReplayConversation()) : EMPTY,
-        of(
-          UIActions.showToast({
-            message: message,
-            type: 'error',
-          }),
-        ),
+        of(UIActions.showErrorToast(translate(message))),
       );
     }),
   );
@@ -1644,7 +1734,23 @@ const saveFoldersEpic: AppEpic = (action$, state$) =>
       conversationsFolders: ConversationsSelectors.selectFolders(state$.value),
     })),
     switchMap(({ conversationsFolders }) => {
-      return ConversationService.setConversationFolders(conversationsFolders);
+      return ConversationService.setConversationFolders(
+        conversationsFolders,
+      ).pipe(
+        catchError((err) => {
+          console.error(
+            'An error occurred during the saving conversation folders: ',
+            err,
+          );
+          return of(
+            UIActions.showErrorToast(
+              translate(
+                'An error occurred during the saving conversation folders',
+              ),
+            ),
+          );
+        }),
+      );
     }),
     ignoreElements(),
   );
@@ -1657,9 +1763,9 @@ const selectConversationsEpic: AppEpic = (action$, state$) =>
         ConversationsActions.selectConversations.match(action) ||
         ConversationsActions.unselectConversations.match(action) ||
         ConversationsActions.updateConversationSuccess.match(action) ||
-        ConversationsActions.createNewConversationSuccess.match(action) ||
+        ConversationsActions.saveNewConversationSuccess.match(action) ||
         ConversationsActions.importConversationsSuccess.match(action) ||
-        ConversationsActions.deleteConversationsSuccess.match(action) ||
+        ConversationsActions.deleteConversationsComplete.match(action) ||
         ConversationsActions.addConversations.match(action) ||
         ConversationsActions.duplicateConversation.match(action) ||
         ConversationsActions.importConversationsSuccess.match(action),
@@ -1721,12 +1827,11 @@ const compareConversationsEpic: AppEpic = (action$, state$) =>
       if (isInvalid) {
         actions.push(
           of(
-            UIActions.showToast({
-              message: translate(
+            UIActions.showErrorToast(
+              translate(
                 'Incorrect conversation was chosen for comparison. Please choose another one.\r\nOnly conversations containing the same number of messages can be compared.',
               ),
-              type: 'error',
-            }),
+            ),
           ),
         );
       } else {
@@ -1972,6 +2077,11 @@ const uploadConversationsByIdsEpic: AppEpic = (action$, state$) =>
           payload.conversationIds.map((id) =>
             ConversationService.getConversation(
               ConversationsSelectors.selectConversation(state$.value, id)!,
+            ).pipe(
+              catchError((err) => {
+                console.error('The selected conversation was not found:', err);
+                return of(null);
+              }),
             ),
           ),
         ),
@@ -2023,7 +2133,17 @@ const saveConversationEpic: AppEpic = (action$) =>
     ),
     switchMap(({ payload: newConversation }) => {
       return ConversationService.updateConversation(newConversation).pipe(
-        switchMap(() => EMPTY), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+        switchMap(() => EMPTY),
+        catchError((err) => {
+          console.error(err);
+          return of(
+            UIActions.showErrorToast(
+              translate(
+                'An error occurred while saving the conversation. Please refresh the page.',
+              ),
+            ),
+          );
+        }),
       );
     }),
   );
@@ -2032,13 +2152,23 @@ const recreateConversationEpic: AppEpic = (action$) =>
   action$.pipe(
     filter(ConversationsActions.recreateConversation.match),
     mergeMap(({ payload }) => {
-      return concat(
-        ConversationService.createConversation(payload.new).pipe(
-          switchMap(() => EMPTY), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
-        ),
+      return zip(
+        ConversationService.createConversation(payload.new),
         ConversationService.deleteConversation(
           getConversationInfoFromId(payload.old.id),
-        ).pipe(switchMap(() => EMPTY)), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+        ),
+      ).pipe(
+        switchMap(() => EMPTY),
+        catchError((err) => {
+          console.error(err);
+          return of(
+            UIActions.showErrorToast(
+              translate(
+                'An error occurred while saving the conversation. Please refresh the page.',
+              ),
+            ),
+          );
+        }),
       );
     }),
   );
@@ -2055,7 +2185,13 @@ const updateConversationEpic: AppEpic = (action$, state$) =>
         values: Partial<Conversation>;
       };
       if (!conversation) {
-        return EMPTY; // TODO: handle?
+        return of(
+          UIActions.showErrorToast(
+            translate(
+              'It looks like this conversation has been deleted. Please reload the page',
+            ),
+          ),
+        );
       }
       const newConversation: Conversation = regenerateConversationId({
         ...(conversation as Conversation),
@@ -2124,16 +2260,29 @@ const uploadConversationsWithFoldersEpic: AppEpic = (action$) =>
             ),
           );
         }),
-        catchError(() =>
-          concat(
+        catchError((err) => {
+          console.error('Error during upload conversations and folders', err);
+          return concat(
             of(
               ConversationsActions.uploadFoldersFail({
                 paths: new Set(payload.paths),
               }),
             ),
             of(ConversationsActions.uploadConversationsFail()),
-          ),
-        ), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+          );
+        }),
+      ),
+    ),
+  );
+
+const uploadConversationsFailEpic: AppEpic = (action$) =>
+  action$.pipe(
+    filter(ConversationsActions.uploadConversationsFail.match),
+    map(() =>
+      UIActions.showErrorToast(
+        translate(
+          'An error occurred while loading conversations and folders. Most likely the conversation already exists. Please refresh the page.',
+        ),
       ),
     ),
   );
@@ -2172,7 +2321,10 @@ const uploadConversationsWithFoldersRecursiveEpic: AppEpic = (action$) =>
             of(ConversationsActions.initFoldersAndConversationsSuccess()),
           );
         }),
-        catchError(() => of(ConversationsActions.uploadConversationsFail())), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+        catchError((err) => {
+          console.error('Error during upload conversations and folders', err);
+          return of(ConversationsActions.uploadConversationsFail());
+        }),
       ),
     ),
   );
@@ -2239,7 +2391,7 @@ export const ConversationsEpics = combineEpics(
   selectConversationsEpic,
   uploadSelectedConversationsEpic,
 
-  createNewConversationSuccessEpic,
+  saveNewConversationEpic,
   createNewConversationsSuccessEpic,
   saveFoldersEpic,
   deleteFolderEpic,
@@ -2271,6 +2423,7 @@ export const ConversationsEpics = combineEpics(
 
   uploadConversationsWithFoldersEpic,
   uploadConversationsWithFoldersRecursiveEpic,
+  uploadConversationsFailEpic,
   toggleFolderEpic,
   openFolderEpic,
   compareConversationsEpic,
diff --git a/apps/chat/src/store/conversations/conversations.reducers.ts b/apps/chat/src/store/conversations/conversations.reducers.ts
index cbf3e01acc..43d4f62e75 100644
--- a/apps/chat/src/store/conversations/conversations.reducers.ts
+++ b/apps/chat/src/store/conversations/conversations.reducers.ts
@@ -215,7 +215,7 @@ export const conversationsSlice = createSlice({
       state,
       _action: PayloadAction<{ conversationIds: string[] }>,
     ) => state,
-    deleteConversationsSuccess: (
+    deleteConversationsComplete: (
       state,
       { payload }: PayloadAction<{ deleteIds: Set<string> }>,
     ) => {
@@ -261,7 +261,11 @@ export const conversationsSlice = createSlice({
       state,
       _action: PayloadAction<ConversationInfo>,
     ) => state,
-    createNewConversationSuccess: (
+    saveNewConversation: (
+      state,
+      _action: PayloadAction<{ newConversation: Conversation }>,
+    ) => state,
+    saveNewConversationSuccess: (
       state,
       {
         payload: { newConversation },
@@ -651,7 +655,6 @@ export const conversationsSlice = createSlice({
     uploadConversationsWithFoldersRecursive: (state) => {
       state.conversationsStatus = UploadStatus.LOADING;
     },
-
     uploadConversationsSuccess: (
       state,
       {
diff --git a/apps/chat/src/store/prompts/prompts.epics.ts b/apps/chat/src/store/prompts/prompts.epics.ts
index e2143fc850..1a38937b5c 100644
--- a/apps/chat/src/store/prompts/prompts.epics.ts
+++ b/apps/chat/src/store/prompts/prompts.epics.ts
@@ -86,21 +86,24 @@ const createNewPromptEpic: AppEpic = (action$, state$) =>
         content: '',
         folderId: getRootId({ apiKey: ApiKeys.Prompts }),
       });
-
-      return of(PromptsActions.createNewPromptSuccess({ newPrompt }));
+      return PromptService.createPrompt(newPrompt).pipe(
+        switchMap(() =>
+          of(PromptsActions.createNewPromptSuccess({ newPrompt })),
+        ),
+        catchError((err) => {
+          console.error("New prompt wasn't created:", err);
+          return of(
+            UIActions.showErrorToast(
+              translate(
+                'An error occurred while creating a new prompt. Most likely the prompt already exists. Please refresh the page.',
+              ),
+            ),
+          );
+        }),
+      );
     }),
   );
 
-const createNewPromptSuccessEpic: AppEpic = (action$) =>
-  action$.pipe(
-    filter(PromptsActions.createNewPromptSuccess.match),
-    switchMap(({ payload }) =>
-      PromptService.createPrompt(payload.newPrompt).pipe(
-        switchMap(() => EMPTY), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
-      ),
-    ),
-  );
-
 const saveFoldersEpic: AppEpic = (action$, state$) =>
   action$.pipe(
     filter(
@@ -117,7 +120,16 @@ const saveFoldersEpic: AppEpic = (action$, state$) =>
       promptsFolders: PromptsSelectors.selectFolders(state$.value),
     })),
     switchMap(({ promptsFolders }) => {
-      return PromptService.setPromptFolders(promptsFolders);
+      return PromptService.setPromptFolders(promptsFolders).pipe(
+        catchError((err) => {
+          console.error('An error occurred during the saving folders', err);
+          return of(
+            UIActions.showErrorToast(
+              translate('An error occurred during the saving folders'),
+            ),
+          );
+        }),
+      );
     }),
     ignoreElements(),
   );
@@ -139,7 +151,12 @@ const getOrUploadPrompt = (
     });
 
     return forkJoin({
-      prompt: PromptService.getPrompt(prompt),
+      prompt: PromptService.getPrompt(prompt).pipe(
+        catchError((err) => {
+          console.error('The prompt was not found:', err);
+          return of(null);
+        }),
+      ),
       payload: of(payload),
     });
   } else {
@@ -154,8 +171,16 @@ const savePromptEpic: AppEpic = (action$) =>
   action$.pipe(
     filter(PromptsActions.savePrompt.match),
     switchMap(({ payload: newPrompt }) => {
-      return PromptService.updatePrompt(newPrompt).pipe(
-        switchMap(() => EMPTY), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+      return PromptService.updatePrompt(newPrompt).pipe(switchMap(() => EMPTY));
+    }),
+    catchError((err) => {
+      console.error(err);
+      return of(
+        UIActions.showErrorToast(
+          translate(
+            'An error occurred while saving the prompt. Please refresh the page.',
+          ),
+        ),
       );
     }),
   );
@@ -165,15 +190,25 @@ const recreatePromptEpic: AppEpic = (action$) =>
     filter(PromptsActions.recreatePrompt.match),
     mergeMap(({ payload }) => {
       const { parentPath } = splitEntityId(payload.old.id);
-      return concat(
-        PromptService.createPrompt(payload.new).pipe(
-          switchMap(() => EMPTY), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
-        ),
+      return zip(
+        PromptService.createPrompt(payload.new),
         PromptService.deletePrompt({
           id: payload.old.id,
           folderId: parentPath || getRootId({ apiKey: ApiKeys.Prompts }),
           name: payload.old.name,
-        }).pipe(switchMap(() => EMPTY)), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+        }),
+      ).pipe(
+        switchMap(() => EMPTY),
+        catchError((err) => {
+          console.error(err);
+          return of(
+            UIActions.showErrorToast(
+              translate(
+                'An error occurred while saving the prompt. Please refresh the page.',
+              ),
+            ),
+          );
+        }),
       );
     }),
   );
@@ -189,7 +224,13 @@ const updatePromptEpic: AppEpic = (action$, state$) =>
       };
 
       if (!prompt) {
-        return EMPTY; // TODO: handle?
+        return of(
+          UIActions.showErrorToast(
+            translate(
+              'It looks like this prompt has been deleted. Please reload the page',
+            ),
+          ),
+        );
       }
 
       const newPrompt: Prompt = {
@@ -217,7 +258,17 @@ export const deletePromptEpic: AppEpic = (action$) =>
     filter(PromptsActions.deletePrompt.match),
     switchMap(({ payload }) => {
       return PromptService.deletePrompt(payload.prompt).pipe(
-        switchMap(() => EMPTY), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+        switchMap(() => EMPTY),
+        catchError((err) => {
+          console.error(err);
+          return of(
+            UIActions.showErrorToast(
+              translate(
+                `An error occurred while saving the prompt "${payload.prompt.name}"`,
+              ),
+            ),
+          );
+        }),
       );
     }),
   );
@@ -240,14 +291,39 @@ const deletePromptsEpic: AppEpic = (action$) =>
       deletePrompts: payload.promptsToRemove,
     })),
     switchMap(({ deletePrompts }) =>
-      concat(
-        of(
-          PromptsActions.deletePromptsSuccess({
-            deletePrompts,
-          }),
+      zip(
+        deletePrompts.map((info) =>
+          PromptService.deletePrompt(info).pipe(
+            switchMap(() => of(null)),
+            catchError((err) => {
+              console.error(
+                `An error occurred while deleting the prompt "${info.name}"`,
+                err,
+              );
+              return info.name;
+            }),
+          ),
         ),
-        zip(deletePrompts.map((id) => PromptService.deletePrompt(id))).pipe(
-          switchMap(() => EMPTY), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+      ).pipe(
+        switchMap((failedNames) =>
+          concat(
+            iif(
+              () => failedNames.filter(Boolean).length > 0,
+              of(
+                UIActions.showErrorToast(
+                  translate(
+                    `An error occurred while saving the prompt(s): "${failedNames.filter(Boolean).join('", "')}"`,
+                  ),
+                ),
+              ),
+              EMPTY,
+            ),
+            of(
+              PromptsActions.deletePromptsComplete({
+                deletePrompts,
+              }),
+            ),
+          ),
         ),
       ),
     ),
@@ -334,6 +410,14 @@ const updateFolderEpic: AppEpic = (action$, state$) =>
 
           return concat(...actions);
         }),
+        catchError((err) => {
+          console.error('An error occurred while updating the folder:', err);
+          return of(
+            UIActions.showErrorToast(
+              translate('An error occurred while updating the folder.'),
+            ),
+          );
+        }),
       );
     }),
   );
@@ -344,7 +428,15 @@ const deleteFolderEpic: AppEpic = (action$, state$) =>
     switchMap(({ payload }) =>
       forkJoin({
         folderId: of(payload.folderId),
-        promptsToRemove: PromptService.getPrompts(payload.folderId, true),
+        promptsToRemove: PromptService.getPrompts(payload.folderId, true).pipe(
+          catchError((err) => {
+            console.error(
+              'An error occurred while uploading prompts and folders:',
+              err,
+            );
+            return [];
+          }),
+        ),
         folders: of(PromptsSelectors.selectFolders(state$.value)),
       }),
     ),
@@ -379,8 +471,17 @@ const deleteFolderEpic: AppEpic = (action$, state$) =>
 const exportPromptsEpic: AppEpic = (action$, state$) =>
   action$.pipe(
     filter(PromptsActions.exportPrompts.match),
-    switchMap(
-      () => PromptService.getPrompts(undefined, true), //listing of all entities
+    switchMap(() =>
+      //listing of all entities
+      PromptService.getPrompts(undefined, true).pipe(
+        catchError((err) => {
+          console.error(
+            'An error occurred while uploading prompts and folders:',
+            err,
+          );
+          return [];
+        }),
+      ),
     ),
     switchMap((promptsListing) => {
       const foldersIds = Array.from(
@@ -400,6 +501,11 @@ const exportPromptsEpic: AppEpic = (action$, state$) =>
         //get all prompts from api
         prompts: zip(
           promptsListing.map((info) => PromptService.getPrompt(info)),
+        ).pipe(
+          catchError((err) => {
+            console.error('An error occurred while uploading prompts:', err);
+            return [];
+          }),
         ),
         folders: of(folders),
       });
@@ -441,7 +547,15 @@ const importPromptsEpic: AppEpic = (action$) =>
     filter(PromptsActions.importPrompts.match),
     switchMap(({ payload }) =>
       forkJoin({
-        promptsListing: PromptService.getPrompts(undefined, true), //listing of all entities
+        promptsListing: PromptService.getPrompts(undefined, true).pipe(
+          catchError((err) => {
+            console.error(
+              'An error occurred while uploading prompts and folders:',
+              err,
+            );
+            return [];
+          }),
+        ), //listing of all entities
         promptsHistory: of(payload.promptsHistory),
       }),
     ),
@@ -469,6 +583,11 @@ const importPromptsEpic: AppEpic = (action$) =>
       //get all prompts from api
       const currentPrompts = zip(
         promptsListing.map((info) => PromptService.getPrompt(info)),
+      ).pipe(
+        catchError((err) => {
+          console.error('An error occurred while uploading prompts:', err);
+          return [];
+        }),
       );
 
       return forkJoin({
@@ -481,12 +600,11 @@ const importPromptsEpic: AppEpic = (action$) =>
       const filteredPrompts = currentPrompts.filter(Boolean) as Prompt[];
       if (!isPromptsFormat(promptsHistory)) {
         return of(
-          UIActions.showToast({
-            message: translate(errorsMessages.unsupportedDataFormat, {
+          UIActions.showErrorToast(
+            translate(errorsMessages.unsupportedDataFormat, {
               ns: 'common',
             }),
-            type: 'error',
-          }),
+          ),
         );
       }
       const preparedPrompts: Prompt[] = getPreparedPrompts({
@@ -509,12 +627,11 @@ const importPromptsEpic: AppEpic = (action$) =>
 
       if (isError) {
         return of(
-          UIActions.showToast({
-            message: translate(errorsMessages.unsupportedDataFormat, {
+          UIActions.showErrorToast(
+            translate(errorsMessages.unsupportedDataFormat, {
               ns: 'common',
             }),
-            type: 'error',
-          }),
+          ),
         );
       }
       return of(PromptsActions.importPromptsSuccess({ prompts, folders }));
@@ -684,17 +801,19 @@ const initPromptsEpic: AppEpic = (action$) =>
         of(PromptsActions.initPromptsSuccess()),
       );
     }),
+    catchError((err) => {
+      console.error(
+        'An error occurred while uploading prompts and folders:',
+        err,
+      );
+      return [];
+    }),
   );
 
 const initEpic: AppEpic = (action$) =>
   action$.pipe(
     filter((action) => PromptsActions.init.match(action)),
-    switchMap(() =>
-      concat(
-        // of(PromptsActions.initFolders()),
-        of(PromptsActions.initPrompts()),
-      ),
-    ),
+    switchMap(() => concat(of(PromptsActions.initPrompts()))),
   );
 
 export const uploadPromptEpic: AppEpic = (action$, state$) =>
@@ -716,6 +835,14 @@ export const uploadPromptEpic: AppEpic = (action$, state$) =>
         originalPromptId: originalPrompt.id,
       });
     }),
+    catchError((err) => {
+      console.error('An error occurred while uploading the prompt:', err);
+      return of(
+        UIActions.showErrorToast(
+          translate('An error occurred while uploading the prompt'),
+        ),
+      );
+    }),
   );
 
 export const PromptsEpics = combineEpics(
@@ -738,7 +865,6 @@ export const PromptsEpics = combineEpics(
   deletePromptsEpic,
   updateFolderEpic,
   createNewPromptEpic,
-  createNewPromptSuccessEpic,
 
   uploadPromptEpic,
 );
diff --git a/apps/chat/src/store/prompts/prompts.reducers.ts b/apps/chat/src/store/prompts/prompts.reducers.ts
index c70bf357fa..d259ec876e 100644
--- a/apps/chat/src/store/prompts/prompts.reducers.ts
+++ b/apps/chat/src/store/prompts/prompts.reducers.ts
@@ -103,7 +103,7 @@ export const promptsSlice = createSlice({
         (p) => !promptToDeleteIds.includes(p.id),
       );
     },
-    deletePromptsSuccess: (
+    deletePromptsComplete: (
       state,
       { payload }: PayloadAction<{ deletePrompts: PromptInfo[] }>,
     ) => {
diff --git a/apps/chat/src/store/ui/ui.epics.ts b/apps/chat/src/store/ui/ui.epics.ts
index 082ea8f8a5..2810c383f9 100644
--- a/apps/chat/src/store/ui/ui.epics.ts
+++ b/apps/chat/src/store/ui/ui.epics.ts
@@ -102,7 +102,31 @@ const saveShowPromptbarEpic: AppEpic = (action$) =>
     ignoreElements(),
   );
 
-const showToastErrorEpic: AppEpic = (action$) =>
+const showErrorToastEpic: AppEpic = (action$) =>
+  action$.pipe(
+    filter(UIActions.showErrorToast.match),
+    switchMap(({ payload }) =>
+      of(UIActions.showToast({ message: payload, type: 'error' })),
+    ),
+  );
+
+const showLoadingToastEpic: AppEpic = (action$) =>
+  action$.pipe(
+    filter(UIActions.showLoadingToast.match),
+    switchMap(({ payload }) =>
+      of(UIActions.showToast({ message: payload, type: 'loading' })),
+    ),
+  );
+
+const showSuccessToastEpic: AppEpic = (action$) =>
+  action$.pipe(
+    filter(UIActions.showSuccessToast.match),
+    switchMap(({ payload }) =>
+      of(UIActions.showToast({ message: payload, type: 'success' })),
+    ),
+  );
+
+const showToastEpic: AppEpic = (action$) =>
   action$.pipe(
     filter(UIActions.showToast.match),
     switchMap(({ payload }) => {
@@ -177,7 +201,10 @@ const UIEpics = combineEpics(
   saveThemeEpic,
   saveShowChatbarEpic,
   saveShowPromptbarEpic,
-  showToastErrorEpic,
+  showToastEpic,
+  showErrorToastEpic,
+  showLoadingToastEpic,
+  showSuccessToastEpic,
   closeAnnouncementEpic,
   saveChatbarWidthEpic,
   savePromptbarWidthEpic,
diff --git a/apps/chat/src/store/ui/ui.reducers.ts b/apps/chat/src/store/ui/ui.reducers.ts
index 07b36d51b7..7ffc6bdcfd 100644
--- a/apps/chat/src/store/ui/ui.reducers.ts
+++ b/apps/chat/src/store/ui/ui.reducers.ts
@@ -104,6 +104,9 @@ export const uiSlice = createSlice({
         response?: Response;
       }>,
     ) => state,
+    showErrorToast: (state, _action: PayloadAction<string>) => state,
+    showLoadingToast: (state, _action: PayloadAction<string>) => state,
+    showSuccessToast: (state, _action: PayloadAction<string>) => state,
     setOpenedFoldersIds: (
       state,
       {
diff --git a/apps/chat/src/utils/app/data/file-service.ts b/apps/chat/src/utils/app/data/file-service.ts
index 48a3eb3f7f..49e37da180 100644
--- a/apps/chat/src/utils/app/data/file-service.ts
+++ b/apps/chat/src/utils/app/data/file-service.ts
@@ -81,6 +81,19 @@ export class FileService {
     );
   }
 
+  private static getListingUrl = ({
+    path,
+    resultQuery,
+  }: {
+    path?: string;
+    resultQuery?: string;
+  }): string => {
+    const listingUrl = encodeApiUrl(
+      constructPath('api/listing', path || getRootId()),
+    );
+    return resultQuery ? `${listingUrl}?${resultQuery}` : listingUrl;
+  };
+
   public static getFileFolders(
     parentPath?: string,
   ): Observable<FileFolderInterface[]> {
@@ -88,14 +101,12 @@ export class FileService {
 
     const query = new URLSearchParams({
       filter,
-      bucket: BucketService.getBucket(),
-      ...(parentPath && {
-        path: parentPath,
-      }),
     });
     const resultQuery = query.toString();
 
-    return ApiUtils.request(`api/${ApiKeys.Files}/listing?${resultQuery}`).pipe(
+    return ApiUtils.request(
+      this.getListingUrl({ path: parentPath, resultQuery }),
+    ).pipe(
       map((folders: BackendFileFolder[]) => {
         return folders.map((folder): FileFolderInterface => {
           const relativePath = folder.parentPath
@@ -146,14 +157,12 @@ export class FileService {
 
     const query = new URLSearchParams({
       filter,
-      bucket: BucketService.getBucket(),
-      ...(parentPath && {
-        path: parentPath,
-      }),
     });
     const resultQuery = query.toString();
 
-    return ApiUtils.request(`api/${ApiKeys.Files}/listing?${resultQuery}`).pipe(
+    return ApiUtils.request(
+      this.getListingUrl({ path: parentPath, resultQuery }),
+    ).pipe(
       map((files: BackendFile[]) => {
         return files.map((file): DialFile => {
           const relativePath = file.parentPath
diff --git a/apps/chat/src/utils/app/data/storages/api-storage.ts b/apps/chat/src/utils/app/data/storages/api-storage.ts
index e4ebe3b876..c4a932e9c9 100644
--- a/apps/chat/src/utils/app/data/storages/api-storage.ts
+++ b/apps/chat/src/utils/app/data/storages/api-storage.ts
@@ -56,7 +56,9 @@ export class ApiStorage implements DialStorage {
             const newName = generateNextName(
               defaultName,
               entity.name,
-              entities.filter((e) => e.folderId === entity.folderId),
+              entities.filter(
+                (e) => e.folderId === entity.folderId && e.id !== entity.id,
+              ),
             );
             const updatedEntity = {
               ...entity,
diff --git a/apps/chat/src/utils/app/data/storages/api/api-entity-storage.ts b/apps/chat/src/utils/app/data/storages/api/api-entity-storage.ts
index 17b987ff39..3adbd9050f 100644
--- a/apps/chat/src/utils/app/data/storages/api/api-entity-storage.ts
+++ b/apps/chat/src/utils/app/data/storages/api/api-entity-storage.ts
@@ -1,4 +1,4 @@
-import { EMPTY, Observable, catchError, map, of } from 'rxjs';
+import { Observable, map } from 'rxjs';
 
 import {
   ApiKeys,
@@ -20,7 +20,7 @@ import { EntityStorage } from '@/src/types/storage';
 
 import { constructPath } from '../../../file';
 import { splitEntityId } from '../../../folders';
-import { BucketService } from '../../bucket-service';
+import { getRootId } from '../../../id';
 
 export abstract class ApiEntityStorage<
   TEntityInfo extends Entity,
@@ -57,23 +57,26 @@ export abstract class ApiEntityStorage<
   private getEntityUrl = (entity: TEntityInfo): string =>
     encodeApiUrl(constructPath('api', entity.id));
 
-  private getListingUrl = (resultQuery: string): string => {
+  private getListingUrl = ({
+    path,
+    resultQuery,
+  }: {
+    path?: string;
+    resultQuery?: string;
+  }): string => {
     const listingUrl = encodeApiUrl(
-      constructPath('api', this.getStorageKey(), 'listing'),
+      constructPath(
+        'api/listing',
+        path || getRootId({ apiKey: this.getStorageKey() }),
+      ),
     );
-    return `${listingUrl}?${resultQuery}`;
+    return resultQuery ? `${listingUrl}?${resultQuery}` : listingUrl;
   };
 
   getFoldersAndEntities(
     path?: string | undefined,
   ): Observable<FoldersAndEntities<TEntityInfo>> {
-    const query = new URLSearchParams({
-      bucket: BucketService.getBucket(),
-      ...(path && { path }),
-    });
-    const resultQuery = query.toString();
-
-    return ApiUtils.request(this.getListingUrl(resultQuery)).pipe(
+    return ApiUtils.request(this.getListingUrl({ path })).pipe(
       map((items: (BackendChatFolder | BackendChatEntity)[]) => {
         const folders = items.filter(
           (item) => item.nodeType === BackendDataNodeType.FOLDER,
@@ -87,12 +90,6 @@ export abstract class ApiEntityStorage<
           folders: folders.map((folder) => this.mapFolder(folder)),
         };
       }),
-      catchError(() =>
-        of({
-          entities: [],
-          folders: [],
-        }),
-      ), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
     );
   }
 
@@ -101,16 +98,13 @@ export abstract class ApiEntityStorage<
 
     const query = new URLSearchParams({
       filter,
-      bucket: BucketService.getBucket(),
-      ...(path && { path }),
     });
     const resultQuery = query.toString();
 
-    return ApiUtils.request(this.getListingUrl(resultQuery)).pipe(
+    return ApiUtils.request(this.getListingUrl({ path, resultQuery })).pipe(
       map((folders: BackendChatFolder[]) => {
         return folders.map((folder) => this.mapFolder(folder));
       }),
-      catchError(() => of([])), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
     );
   }
 
@@ -119,17 +113,14 @@ export abstract class ApiEntityStorage<
 
     const query = new URLSearchParams({
       filter,
-      bucket: BucketService.getBucket(),
-      ...(path && { path }),
       ...(recursive && { recursive: String(recursive) }),
     });
     const resultQuery = query.toString();
 
-    return ApiUtils.request(this.getListingUrl(resultQuery)).pipe(
+    return ApiUtils.request(this.getListingUrl({ path, resultQuery })).pipe(
       map((entities: BackendChatEntity[]) => {
         return entities.map((entity) => this.mapEntity(entity));
       }),
-      catchError(() => of([])), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
     );
   }
 
@@ -141,7 +132,6 @@ export abstract class ApiEntityStorage<
           status: UploadStatus.LOADED,
         };
       }),
-      catchError(() => of(null)), // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
     );
   }
 
@@ -152,7 +142,7 @@ export abstract class ApiEntityStorage<
         'Content-Type': 'application/json',
       },
       body: JSON.stringify(this.cleanUpEntity(entity)),
-    }); // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+    });
   }
 
   updateEntity(entity: TEntity): Observable<void> {
@@ -162,7 +152,7 @@ export abstract class ApiEntityStorage<
         'Content-Type': 'application/json',
       },
       body: JSON.stringify(this.cleanUpEntity(entity)),
-    }).pipe(catchError(() => EMPTY)); // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+    });
   }
 
   deleteEntity(info: TEntityInfo): Observable<void> {
@@ -171,7 +161,7 @@ export abstract class ApiEntityStorage<
       headers: {
         'Content-Type': 'application/json',
       },
-    }).pipe(catchError(() => EMPTY)); // TODO: handle error it in https://github.com/epam/ai-dial-chat/issues/663
+    });
   }
 
   abstract getEntityKey(info: TEntityInfo): string;
diff --git a/apps/chat/src/utils/app/data/storages/api/conversation-api-storage.ts b/apps/chat/src/utils/app/data/storages/api/conversation-api-storage.ts
index d70d5e63d2..59ede29d4a 100644
--- a/apps/chat/src/utils/app/data/storages/api/conversation-api-storage.ts
+++ b/apps/chat/src/utils/app/data/storages/api/conversation-api-storage.ts
@@ -1,4 +1,4 @@
-import { Observable, forkJoin, of } from 'rxjs';
+import { Observable, catchError, forkJoin, of } from 'rxjs';
 
 import { getRootId } from '@/src/utils/app/id';
 import {
@@ -66,7 +66,12 @@ export const getOrUploadConversation = (
 
   if (conversation?.status !== UploadStatus.LOADED) {
     return forkJoin({
-      conversation: ConversationService.getConversation(conversation),
+      conversation: ConversationService.getConversation(conversation).pipe(
+        catchError((err) => {
+          console.error('The conversation was not found:', err);
+          return of(null);
+        }),
+      ),
       payload: of(payload),
     });
   } else {
diff --git a/apps/chat/src/utils/server/api.ts b/apps/chat/src/utils/server/api.ts
index 6b4b1c43ec..1267f517aa 100644
--- a/apps/chat/src/utils/server/api.ts
+++ b/apps/chat/src/utils/server/api.ts
@@ -11,7 +11,6 @@ import { PromptInfo } from '@/src/types/prompt';
 import { EMPTY_MODEL_ID } from '@/src/constants/default-settings';
 
 import { constructPath } from '../app/file';
-import { OpenAIError } from './error';
 
 export enum ApiKeys {
   Files = 'files',
@@ -67,7 +66,7 @@ export const getEntityTypeFromPath = (
   return Array.isArray(req.query.entitytype) ? '' : req.query.entitytype;
 };
 
-const encodeSlugs = (slugs: (string | undefined)[]): string =>
+export const encodeSlugs = (slugs: (string | undefined)[]): string =>
   constructPath(
     ...slugs.filter(Boolean).map((part) => encodeURIComponent(part as string)),
   );
@@ -78,22 +77,6 @@ export const encodeApiUrl = (path: string): string =>
 export const decodeApiUrl = (path: string): string =>
   constructPath(...path.split('/').map((part) => decodeURIComponent(part)));
 
-export const getEntityUrlFromSlugs = (
-  dialApiHost: string,
-  req: NextApiRequest,
-): string => {
-  const entityType = getEntityTypeFromPath(req);
-  const slugs = Array.isArray(req.query.slug)
-    ? req.query.slug
-    : [req.query.slug];
-
-  if (!slugs || slugs.length === 0) {
-    throw new OpenAIError(`No ${entityType} path provided`, '', '', '404');
-  }
-
-  return `${dialApiHost}/v1/${entityType}/${encodeSlugs(slugs)}`;
-};
-
 const pathKeySeparator = '__';
 const encodedKeySeparator = '%5F%5F';