diff --git a/components/book/AddNewBookForm.tsx b/components/book/AddNewBookForm.tsx
index 2e4df44..b9ff37e 100644
--- a/components/book/AddNewBookForm.tsx
+++ b/components/book/AddNewBookForm.tsx
@@ -27,7 +27,7 @@ import GuideTour, {GuideStep} from "@/components/GuideTour";
 import {UserProps} from "@/lib/models/User";
 import {useTranslations} from "next-intl";
 import {LangContext, LangContextProps} from "@/context/LangContext";
-// TODO: Refactor to use window.electron.invoke() instead of OfflineDataService
+import OfflineContext, {OfflineContextType} from "@/context/OfflineContext";
 
 interface MinMax {
     min: number;
@@ -39,6 +39,7 @@ export default function AddNewBookForm({setCloseForm}: { setCloseForm: Dispatch<
     const {lang} = useContext<LangContextProps>(LangContext);
     const {session, setSession} = useContext(SessionContext);
     const {errorMessage} = useContext(AlertContext);
+    const {isCurrentlyOffline} = useContext<OfflineContextType>(OfflineContext);
     const modalRef: React.RefObject<HTMLDivElement | null> = useRef<HTMLDivElement>(null);
     
     const [title, setTitle] = useState<string>('');
@@ -123,7 +124,6 @@ export default function AddNewBookForm({setCloseForm}: { setCloseForm: Dispatch<
         }
         setIsAddingBook(true);
         try {
-            const offlineDataService = getOfflineDataService();
             const bookData = {
                 title,
                 subTitle: subtitle,
@@ -134,26 +134,25 @@ export default function AddNewBookForm({setCloseForm}: { setCloseForm: Dispatch<
                 desiredWordCount: wordCount
             };
 
-            const bookId: string = await offlineDataService.createBook(
-                bookData,
-                session.user?.id || '',
-                async () => {
-                    // Only called if online
-                    const id = await System.authPostToServer<string>('book/add', {
-                        title: title,
-                        subTitle: subtitle,
-                        type: selectedBookType,
-                        summary: summary,
-                        serie: 0,
-                        publicationDate: publicationDate,
-                        desiredWordCount: wordCount,
-                    }, token, lang);
-                    if (!id) {
-                        throw new Error(t('addNewBookForm.error.addingBook'));
-                    }
-                    return id;
+            let bookId: string;
+            if (!isCurrentlyOffline()) {
+                // Online - call API server
+                bookId = await System.authPostToServer<string>('book/add', {
+                    title: title,
+                    subTitle: subtitle,
+                    type: selectedBookType,
+                    summary: summary,
+                    serie: 0,
+                    publicationDate: publicationDate,
+                    desiredWordCount: wordCount,
+                }, token, lang);
+                if (!bookId) {
+                    throw new Error(t('addNewBookForm.error.addingBook'));
                 }
-            );
+            } else {
+                // Offline - call local database
+                bookId = await window.electron.invoke<string>('db:book:create', bookData);
+            }
 
             const book: BookProps = {
                 bookId: bookId,
diff --git a/electron/database/models/Book.ts b/electron/database/models/Book.ts
index 82a46bf..ebd07d0 100644
--- a/electron/database/models/Book.ts
+++ b/electron/database/models/Book.ts
@@ -18,8 +18,7 @@ import fs from "fs";
 import BookRepo from "../repositories/book.repository.js";
 import Chapter, {ActChapter, ChapterContentData, ChapterProps} from "./Chapter.js";
 import UserRepo from "../repositories/user.repository.js";
-import ChapterRepo from "@/electron/database/repositories/chapter.repository";
-import {mainStyle} from "@/electron/database/models/EpubStyle";
+import ChapterRepo from "../repositories/chapter.repository.js";
 
 export interface BookProps{
     id:string;
diff --git a/electron/database/models/Chapter.ts b/electron/database/models/Chapter.ts
index 1e143a8..c1cd358 100644
--- a/electron/database/models/Chapter.ts
+++ b/electron/database/models/Chapter.ts
@@ -8,9 +8,9 @@ import ChapterRepo, {
     CompanionContentQueryResult,
     ChapterStoryQueryResult,
     ContentQueryResult
-} from "@/electron/database/repositories/chapter.repository";
-import System from "../System";
-import {getUserEncryptionKey} from "../keyManager";
+} from "../repositories/chapter.repository.js";
+import System from "../System.js";
+import {getUserEncryptionKey} from "../keyManager.js";
 import { generateHTML } from "@tiptap/react";
 
 export interface ChapterContent {
diff --git a/electron/database/models/Character.ts b/electron/database/models/Character.ts
index a79fcaf..3c34620 100644
--- a/electron/database/models/Character.ts
+++ b/electron/database/models/Character.ts
@@ -2,9 +2,9 @@ import CharacterRepo, {
     AttributeResult,
     CharacterResult,
     CompleteCharacterResult
-} from "@/electron/database/repositories/character.repository";
-import System from "@/electron/database/System";
-import {getUserEncryptionKey} from "../keyManager";
+} from "../repositories/character.repository.js";
+import System from "../System.js";
+import {getUserEncryptionKey} from "../keyManager.js";
 
 export type CharacterCategory = 'Main' | 'Secondary' | 'Recurring';
 
diff --git a/electron/database/models/Location.ts b/electron/database/models/Location.ts
index 1814f1c..248016a 100644
--- a/electron/database/models/Location.ts
+++ b/electron/database/models/Location.ts
@@ -2,9 +2,9 @@ import LocationRepo, {
     LocationByTagResult,
     LocationElementQueryResult,
     LocationQueryResult
-} from "@/electron/database/repositories/location.repository";
-import System from "@/electron/database/System";
-import {getUserEncryptionKey} from "../keyManager";
+} from "../repositories/location.repository.js";
+import System from "../System.js";
+import {getUserEncryptionKey} from "../keyManager.js";
 
 export interface SubElement {
     id: string;
diff --git a/electron/database/models/User.ts b/electron/database/models/User.ts
index f3e12c2..d606a54 100644
--- a/electron/database/models/User.ts
+++ b/electron/database/models/User.ts
@@ -1,7 +1,7 @@
-import UserRepo, {UserAccountQuery, UserInfosQueryResponse} from "@/electron/database/repositories/user.repository";
-import System from "@/electron/database/System";
-import Book, {BookProps} from "@/electron/database/models/Book";
-import {getUserEncryptionKey} from "@/electron/database/keyManager";
+import UserRepo, {UserAccountQuery, UserInfosQueryResponse} from "../repositories/user.repository.js";
+import System from "../System.js";
+import Book, {BookProps} from "./Book.js";
+import {getUserEncryptionKey} from "../keyManager.js";
 
 interface UserAccount{
     firstName:string;
diff --git a/electron/database/repositories/book.repository.ts b/electron/database/repositories/book.repository.ts
index 805e2e3..3e99ab1 100644
--- a/electron/database/repositories/book.repository.ts
+++ b/electron/database/repositories/book.repository.ts
@@ -1,5 +1,5 @@
 import {Database, QueryResult, RunResult, SQLiteValue} from 'node-sqlite3-wasm';
-import System from "@/electron/database/System";
+import System from "../System.js";
 
 export interface BookQuery extends Record<string, SQLiteValue> {
     book_id: string;
diff --git a/electron/database/repositories/chapter.repository.ts b/electron/database/repositories/chapter.repository.ts
index 5b6597f..273fa58 100644
--- a/electron/database/repositories/chapter.repository.ts
+++ b/electron/database/repositories/chapter.repository.ts
@@ -1,5 +1,5 @@
 import {Database, RunResult, SQLiteValue} from 'node-sqlite3-wasm';
-import System from "../System";
+import System from "../System.js";
 
 export interface ChapterContentQueryResult extends Record<string, SQLiteValue>{
     chapter_id: string;
diff --git a/electron/database/repositories/character.repository.ts b/electron/database/repositories/character.repository.ts
index ab35f98..f1bf243 100644
--- a/electron/database/repositories/character.repository.ts
+++ b/electron/database/repositories/character.repository.ts
@@ -1,5 +1,5 @@
 import {Database, RunResult, SQLiteValue} from 'node-sqlite3-wasm';
-import System from "../System";
+import System from "../System.js";
 
 export interface CharacterResult extends Record<string, SQLiteValue> {
     character_id: string;
diff --git a/electron/database/repositories/location.repository.ts b/electron/database/repositories/location.repository.ts
index 15ff35c..a3bd84e 100644
--- a/electron/database/repositories/location.repository.ts
+++ b/electron/database/repositories/location.repository.ts
@@ -1,5 +1,5 @@
 import {Database, RunResult, SQLiteValue} from 'node-sqlite3-wasm';
-import System from "../System";
+import System from "../System.js";
 
 export interface LocationQueryResult extends Record<string, SQLiteValue> {
     loc_id: string;
diff --git a/electron/database/repositories/user.repository.ts b/electron/database/repositories/user.repository.ts
index fbdca85..c8c64ff 100644
--- a/electron/database/repositories/user.repository.ts
+++ b/electron/database/repositories/user.repository.ts
@@ -1,5 +1,5 @@
 import {Database, RunResult, SQLiteValue} from 'node-sqlite3-wasm';
-import System from "../System";
+import System from "../System.js";
 
 export interface UserInfosQueryResponse extends Record<string, SQLiteValue> {
     first_name: string;
diff --git a/electron/main.ts b/electron/main.ts
index 39e9f1f..4b0fe43 100644
--- a/electron/main.ts
+++ b/electron/main.ts
@@ -222,192 +222,8 @@ ipcMain.handle('db-initialize', (_event, userId: string, encryptionKey: string)
   }
 });
 
-/**
- * Get all books
- */
-ipcMain.handle('db-get-books', () => {
-  try {
-    const db = getDatabaseService();
-    const books = db.getBooks();
-    return { success: true, data: books };
-  } catch (error) {
-    console.error('Failed to get books:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Get single book with all data
- */
-ipcMain.handle('db-get-book', (_event, bookId: string) => {
-  try {
-    const db = getDatabaseService();
-    const book = db.getBook(bookId);
-    return { success: true, data: book };
-  } catch (error) {
-    console.error('Failed to get book:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Save book
- */
-ipcMain.handle('db-save-book', (_event, book: any, authorId?: string) => {
-  try {
-    const db = getDatabaseService();
-    db.saveBook(book, authorId);
-    return { success: true };
-  } catch (error) {
-    console.error('Failed to save book:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Delete book
- */
-ipcMain.handle('db-delete-book', (_event, bookId: string) => {
-  try {
-    const db = getDatabaseService();
-    db.deleteBook(bookId);
-    return { success: true };
-  } catch (error) {
-    console.error('Failed to delete book:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Save chapter
- */
-ipcMain.handle('db-save-chapter', (_event, chapter: any, bookId: string, contentId?: string) => {
-  try {
-    const db = getDatabaseService();
-    db.saveChapter(chapter, bookId, contentId);
-    return { success: true };
-  } catch (error) {
-    console.error('Failed to save chapter:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Get characters for a book
- */
-ipcMain.handle('db-get-characters', (_event, bookId: string) => {
-  try {
-    const db = getDatabaseService();
-    const characters = db.getCharacters(bookId);
-    return { success: true, data: characters };
-  } catch (error) {
-    console.error('Failed to get characters:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Save character
- */
-ipcMain.handle('db-save-character', (_event, character: any, bookId: string) => {
-  try {
-    const db = getDatabaseService();
-    db.saveCharacter(character, bookId);
-    return { success: true };
-  } catch (error) {
-    console.error('Failed to save character:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Get AI conversations for a book
- */
-ipcMain.handle('db-get-conversations', (_event, bookId: string) => {
-  try {
-    const db = getDatabaseService();
-    const conversations = db.getConversations(bookId);
-    return { success: true, data: conversations };
-  } catch (error) {
-    console.error('Failed to get conversations:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Save AI conversation
- */
-ipcMain.handle('db-save-conversation', (_event, conversation: any, bookId: string) => {
-  try {
-    const db = getDatabaseService();
-    db.saveConversation(conversation, bookId);
-    return { success: true };
-  } catch (error) {
-    console.error('Failed to save conversation:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Get sync status
- */
-ipcMain.handle('db-get-sync-status', () => {
-  try {
-    const db = getDatabaseService();
-    const status = db.getSyncStatus();
-    return { success: true, data: status };
-  } catch (error) {
-    console.error('Failed to get sync status:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
-
-/**
- * Get pending changes
- */
-ipcMain.handle('db-get-pending-changes', (_event, limit: number = 100) => {
-  try {
-    const db = getDatabaseService();
-    const changes = db.getPendingChanges(limit);
-    return { success: true, data: changes };
-  } catch (error) {
-    console.error('Failed to get pending changes:', error);
-    return {
-      success: false,
-      error: error instanceof Error ? error.message : 'Unknown error'
-    };
-  }
-});
+// NOTE: All database IPC handlers have been moved to ./ipc/book.ipc.ts
+// and use the new createHandler() pattern with auto userId/lang injection
 
 app.whenReady().then(() => {
   console.log('App ready, isDev:', isDev);
diff --git a/lib/db/sync.service.ts b/lib/db/sync.service.ts
index 2e9012e..7cdc252 100644
--- a/lib/db/sync.service.ts
+++ b/lib/db/sync.service.ts
@@ -21,11 +21,8 @@ export async function getSyncStatus(): Promise<SyncProgress> {
     }
 
     try {
-        const result = await window.electron.dbGetSyncStatus();
-        if (!result.success) {
-            throw new Error(result.error);
-        }
-        return result.data;
+        const result = await window.electron.invoke<SyncProgress>('db:sync:status');
+        return result;
     } catch (error) {
         console.error('Failed to get sync status:', error);
         return {
@@ -46,11 +43,8 @@ export async function getPendingChanges(limit: number = 100) {
     }
 
     try {
-        const result = await window.electron.dbGetPendingChanges(limit);
-        if (!result.success) {
-            throw new Error(result.error);
-        }
-        return result.data || [];
+        const result = await window.electron.invoke<any[]>('db:sync:pending-changes', limit);
+        return result || [];
     } catch (error) {
         console.error('Failed to get pending changes:', error);
         return [];