diff --git a/frontend/components/Area/AreaModal.tsx b/frontend/components/Area/AreaModal.tsx
index 080c824..d5f5ff1 100644
--- a/frontend/components/Area/AreaModal.tsx
+++ b/frontend/components/Area/AreaModal.tsx
@@ -8,7 +8,7 @@ interface AreaModalProps {
     isOpen: boolean;
     onClose: () => void;
     onSave: (areaData: Partial<Area>) => Promise<void>;
-    onDelete?: (areaId: number) => Promise<void>;
+    onDelete?: (areaUid: string) => Promise<void>;
     area?: Area | null;
 }
 
diff --git a/frontend/components/Areas.tsx b/frontend/components/Areas.tsx
index 7e12478..134c362 100644
--- a/frontend/components/Areas.tsx
+++ b/frontend/components/Areas.tsx
@@ -273,7 +273,7 @@ const Areas: React.FC = () => {
                         isOpen={isAreaModalOpen}
                         onClose={() => setIsAreaModalOpen(false)}
                         onSave={handleSaveArea}
-                        onDelete={async (areaUid) => {
+                        onDelete={async (areaUid: string) => {
                             try {
                                 await deleteArea(areaUid);
                                 const updatedAreas = await fetchAreas();
diff --git a/frontend/components/Inbox/InboxItemDetail.tsx b/frontend/components/Inbox/InboxItemDetail.tsx
index 98e1033..254e400 100644
--- a/frontend/components/Inbox/InboxItemDetail.tsx
+++ b/frontend/components/Inbox/InboxItemDetail.tsx
@@ -663,8 +663,20 @@ const InboxItemDetail: React.FC<InboxItemDetailProps> = ({
                                     type="button"
                                     onClick={(e) => {
                                         e.stopPropagation();
-                                        if (onUpdate && item.id !== undefined) {
-                                            onUpdate(item.id);
+                                        if (onUpdate) {
+                                            const identifier =
+                                                item.uid ??
+                                                (item.id !== undefined
+                                                    ? String(item.id)
+                                                    : null);
+
+                                            if (identifier) {
+                                                onUpdate(identifier);
+                                            } else {
+                                                console.warn(
+                                                    'Inbox item is missing an identifier for update.'
+                                                );
+                                            }
                                         }
                                         setIsDropdownOpen(false);
                                     }}
diff --git a/frontend/components/Note/NoteDetails.tsx b/frontend/components/Note/NoteDetails.tsx
index 0b9b896..5497506 100644
--- a/frontend/components/Note/NoteDetails.tsx
+++ b/frontend/components/Note/NoteDetails.tsx
@@ -70,14 +70,20 @@ const NoteDetails: React.FC = () => {
 
     const handleSaveNote = async (updatedNote: Note) => {
         try {
-            if (updatedNote.id !== undefined) {
+            const noteIdentifier =
+                updatedNote.uid ??
+                (updatedNote.id !== undefined
+                    ? String(updatedNote.id)
+                    : null);
+
+            if (noteIdentifier) {
                 const savedNote = await apiUpdateNote(
-                    updatedNote.id,
+                    noteIdentifier,
                     updatedNote
                 );
                 setNote(savedNote);
             } else {
-                console.error('Error: Note ID is undefined.');
+                console.error('Error: Note identifier is undefined.');
             }
         } catch (err) {
             console.error('Error saving note:', err);
diff --git a/frontend/components/Project/ProjectDetails.tsx b/frontend/components/Project/ProjectDetails.tsx
index 7c267ed..ffe5229 100644
--- a/frontend/components/Project/ProjectDetails.tsx
+++ b/frontend/components/Project/ProjectDetails.tsx
@@ -546,10 +546,17 @@ const ProjectDetails: React.FC = () => {
         setIsNoteModalOpen(true);
     };
 
-    const handleDeleteNote = async (noteId: number) => {
+    const handleDeleteNote = async (noteIdentifier: string) => {
         try {
-            await apiDeleteNote(noteId);
-            setNotes(notes.filter((n) => n.id !== noteId));
+            await apiDeleteNote(noteIdentifier);
+            setNotes(
+                notes.filter((n) => {
+                    const currentIdentifier =
+                        n.uid ??
+                        (n.id !== undefined ? String(n.id) : undefined);
+                    return currentIdentifier !== noteIdentifier;
+                })
+            );
             setNoteToDelete(null);
             setIsConfirmDialogOpen(false);
         } catch {
@@ -561,8 +568,17 @@ const ProjectDetails: React.FC = () => {
     const handleSaveNote = async (noteData: Note) => {
         try {
             let savedNote: Note;
-            if (noteData.id) {
-                savedNote = await updateNote(noteData.id, noteData);
+            const noteIdentifier =
+                noteData.uid ??
+                (noteData.id !== undefined
+                    ? String(noteData.id)
+                    : null);
+
+            let isUpdate = false;
+
+            if (noteIdentifier) {
+                savedNote = await updateNote(noteIdentifier, noteData);
+                isUpdate = true;
             } else {
                 savedNote = await createNote(noteData);
             }
@@ -575,9 +591,25 @@ const ProjectDetails: React.FC = () => {
             // If updated note moved to another project, remove it from this list
             if (savedNote.id && savedNote.project_id !== project?.id) {
                 setNotes(notes.filter((n) => n.id !== savedNote.id));
-            } else if (noteData.id) {
+            } else if (isUpdate) {
+                const savedIdentifier =
+                    savedNote.uid ??
+                    (savedNote.id !== undefined
+                        ? String(savedNote.id)
+                        : null);
+
                 setNotes(
-                    notes.map((n) => (n.uid === savedNote.uid ? savedNote : n))
+                    notes.map((n) => {
+                        const currentIdentifier =
+                            n.uid ??
+                            (n.id !== undefined
+                                ? String(n.id)
+                                : undefined);
+
+                        return currentIdentifier === savedIdentifier
+                            ? savedNote
+                            : n;
+                    })
                 );
             } else {
                 setNotes([savedNote, ...notes]);
@@ -1217,7 +1249,17 @@ const ProjectDetails: React.FC = () => {
                     <ConfirmDialog
                         title="Delete Note"
                         message={`Are you sure you want to delete the note "${noteToDelete.title}"?`}
-                        onConfirm={() => handleDeleteNote(noteToDelete.id!)}
+                        onConfirm={() => {
+                            const identifier =
+                                noteToDelete?.uid ??
+                                (noteToDelete?.id !== undefined
+                                    ? String(noteToDelete.id)
+                                    : null);
+
+                            if (identifier) {
+                                handleDeleteNote(identifier);
+                            }
+                        }}
                         onCancel={() => {
                             setIsConfirmDialogOpen(false);
                             setNoteToDelete(null);
diff --git a/frontend/components/Shared/NoteCard.tsx b/frontend/components/Shared/NoteCard.tsx
index a3e2780..53415f4 100644
--- a/frontend/components/Shared/NoteCard.tsx
+++ b/frontend/components/Shared/NoteCard.tsx
@@ -7,19 +7,12 @@ import {
     EllipsisVerticalIcon,
 } from '@heroicons/react/24/outline';
 import MarkdownRenderer from './MarkdownRenderer';
+import { Note } from '../../entities/Note';
 
 interface NoteCardProps {
-    note: {
-        uid: string;
-        title: string;
-        content?: string;
-        tags?: { name: string; uid?: string }[];
-        Tags?: { name: string; uid?: string }[];
-        project?: { name: string; id?: number; uid?: string };
-        Project?: { name: string; id?: number; uid?: string };
-    };
-    onEdit?: (note: any) => void;
-    onDelete?: (note: any) => void;
+    note: Note;
+    onEdit?: (note: Note) => void;
+    onDelete?: (note: Note) => void;
     showActions?: boolean;
     showProject?: boolean;
 }
@@ -38,6 +31,8 @@ const NoteCard: React.FC<NoteCardProps> = ({
 
     const tags = note.tags || note.Tags || [];
     const project = note.project || note.Project;
+    const noteIdentifier =
+        note.uid ?? (note.id !== undefined ? String(note.id) : 'note');
 
     useEffect(() => {
         const handleClickOutside = (event: MouseEvent) => {
@@ -61,7 +56,7 @@ const NoteCard: React.FC<NoteCardProps> = ({
     return (
         <div className="relative group">
             <Link
-                to={`/note/${note.uid}-${note.title
+                to={`/note/${noteIdentifier}-${note.title
                     .toLowerCase()
                     .replace(/[^a-z0-9]+/g, '-')
                     .replace(/^-|-$/g, '')}`}
@@ -206,7 +201,7 @@ const NoteCard: React.FC<NoteCardProps> = ({
                         className="text-gray-500 hover:text-gray-700 dark:text-gray-300 dark:hover:text-gray-400 focus:outline-none transition-opacity duration-300 p-1"
                         aria-label={t('notes.toggleDropdownMenu')}
                         type="button"
-                        data-testid={`note-dropdown-${note.uid}`}
+                        data-testid={`note-dropdown-${noteIdentifier}`}
                     >
                         <EllipsisVerticalIcon className="h-4 w-4" />
                     </button>
@@ -222,7 +217,7 @@ const NoteCard: React.FC<NoteCardProps> = ({
                                         setDropdownOpen(false);
                                     }}
                                     className="block px-4 py-2 text-sm text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-600 w-full text-left rounded-t-md"
-                                    data-testid={`note-edit-${note.uid}`}
+                                    data-testid={`note-edit-${noteIdentifier}`}
                                 >
                                     {t('notes.edit', 'Edit')}
                                 </button>
@@ -236,7 +231,7 @@ const NoteCard: React.FC<NoteCardProps> = ({
                                         setDropdownOpen(false);
                                     }}
                                     className="block px-4 py-2 text-sm text-red-500 dark:text-red-300 hover:bg-gray-100 dark:hover:bg-gray-600 w-full text-left rounded-b-md"
-                                    data-testid={`note-delete-${note.uid}`}
+                                    data-testid={`note-delete-${noteIdentifier}`}
                                 >
                                     {t('notes.delete', 'Delete')}
                                 </button>