diff --git a/pocketbooksync/README.md b/pocketbooksync/README.md
new file mode 100644
index 0000000..b3ba005
--- /dev/null
+++ b/pocketbooksync/README.md
@@ -0,0 +1,19 @@
+# PocketBook Sync (Nextcloud App)
+
+This app syncs PocketBook Cloud highlights/notes into Nextcloud markdown files:
+
+- One markdown file per book.
+- File name format: `Book Title - Author.md`.
+- Personal settings page for credentials, target folder, sync interval.
+- Connection test + last sync status.
+- Background job that checks each user's configured interval.
+
+## Notes on PocketBook API
+
+The app currently expects these endpoints:
+
+- `POST /api/v1/auth/login` with `{ "email": "...", "password": "..." }` and response `{ "token": "..." }`
+- `GET /api/v1/library/books?includeAnnotations=true` with Bearer token and response `{ "books": [...] }`
+
+If your PocketBook Cloud account uses different endpoints/field names,
+adapt `lib/Service/PocketBookClient.php` accordingly.
diff --git a/pocketbooksync/appinfo/app.php b/pocketbooksync/appinfo/app.php
new file mode 100644
index 0000000..547d051
--- /dev/null
+++ b/pocketbooksync/appinfo/app.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\PocketBookSync\AppInfo;
+
+use OCP\AppFramework\App;
+
+class Application extends App {
+	public const APP_ID = 'pocketbooksync';
+
+	public function __construct() {
+		parent::__construct(self::APP_ID);
+	}
+}
diff --git a/pocketbooksync/appinfo/info.xml b/pocketbooksync/appinfo/info.xml
new file mode 100644
index 0000000..4a0c6b8
--- /dev/null
+++ b/pocketbooksync/appinfo/info.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0"?>
+<info>
+	<id>pocketbooksync</id>
+	<name>PocketBook Sync</name>
+	<summary>Sync PocketBook Cloud highlights and notes into markdown files</summary>
+	<description>Connects a user's PocketBook Cloud account and regularly syncs book highlights into one markdown file per book.</description>
+	<version>0.1.0</version>
+	<licence>agpl</licence>
+	<author mail="dev@example.com">Codex</author>
+	<namespace>PocketBookSync</namespace>
+	<category>productivity</category>
+	<settings>
+		<personal>OCA\PocketBookSync\Settings\Personal</personal>
+	</settings>
+	<background-jobs>
+		<job>OCA\PocketBookSync\BackgroundJob\SyncJob</job>
+	</background-jobs>
+	<dependencies>
+		<nextcloud min-version="29" max-version="31"/>
+	</dependencies>
+</info>
diff --git a/pocketbooksync/appinfo/routes.php b/pocketbooksync/appinfo/routes.php
new file mode 100644
index 0000000..1b81cec
--- /dev/null
+++ b/pocketbooksync/appinfo/routes.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+return [
+	'routes' => [
+		[
+			'name' => 'Settings#get',
+			'url' => '/settings',
+			'verb' => 'GET',
+		],
+		[
+			'name' => 'Settings#save',
+			'url' => '/settings',
+			'verb' => 'POST',
+		],
+		[
+			'name' => 'Settings#testConnection',
+			'url' => '/settings/test-connection',
+			'verb' => 'POST',
+		],
+		[
+			'name' => 'Settings#syncNow',
+			'url' => '/settings/sync-now',
+			'verb' => 'POST',
+		],
+	],
+];
diff --git a/pocketbooksync/js/settings.js b/pocketbooksync/js/settings.js
new file mode 100644
index 0000000..3b6056a
--- /dev/null
+++ b/pocketbooksync/js/settings.js
@@ -0,0 +1,87 @@
+(function () {
+	const root = document.getElementById('pocketbooksync-settings');
+	if (!root) {
+		return;
+	}
+
+	const requestToken = document.querySelector('head').dataset.requesttoken;
+	const basePath = OC.generateUrl('/apps/pocketbooksync');
+
+	const fields = {
+		baseUrl: root.querySelector('#pbs-base-url'),
+		username: root.querySelector('#pbs-username'),
+		password: root.querySelector('#pbs-password'),
+		targetFolder: root.querySelector('#pbs-target-folder'),
+		syncIntervalMin: root.querySelector('#pbs-sync-interval'),
+	};
+	const status = root.querySelector('#pbs-status');
+	const lastSync = root.querySelector('#pbs-last-sync');
+
+	async function api(path, method, body) {
+		const response = await fetch(basePath + path, {
+			method,
+			headers: {
+				'Content-Type': 'application/json',
+				requesttoken: requestToken,
+			},
+			body: body ? JSON.stringify(body) : undefined,
+		});
+		const payload = await response.json();
+		if (!response.ok) {
+			throw new Error(payload.error || 'Request failed');
+		}
+		return payload;
+	}
+
+	function fillForm(data) {
+		fields.baseUrl.value = data.baseUrl || '';
+		fields.username.value = data.username || '';
+		fields.password.value = data.password || '';
+		fields.targetFolder.value = data.targetFolder || '/PocketBook Highlights';
+		fields.syncIntervalMin.value = data.syncIntervalMin || 60;
+		status.textContent = 'Status: ' + (data.lastStatus || 'Never synced');
+		if (data.lastSync) {
+			lastSync.textContent = 'Last sync: ' + new Date(parseInt(data.lastSync, 10) * 1000).toLocaleString();
+		}
+	}
+
+	function collect() {
+		return {
+			baseUrl: fields.baseUrl.value,
+			username: fields.username.value,
+			password: fields.password.value,
+			targetFolder: fields.targetFolder.value,
+			syncIntervalMin: parseInt(fields.syncIntervalMin.value, 10) || 60,
+		};
+	}
+
+	root.querySelector('#pbs-save').addEventListener('click', async () => {
+		await api('/settings', 'POST', collect());
+		status.textContent = 'Status: settings saved';
+	});
+
+	root.querySelector('#pbs-test').addEventListener('click', async () => {
+		status.textContent = 'Status: testing connection...';
+		try {
+			const result = await api('/settings/test-connection', 'POST');
+			status.textContent = result.ok ? 'Status: connection OK' : 'Status: connection failed';
+		} catch (e) {
+			status.textContent = 'Status: connection failed (' + e.message + ')';
+		}
+	});
+
+	root.querySelector('#pbs-sync').addEventListener('click', async () => {
+		status.textContent = 'Status: syncing...';
+		try {
+			const result = await api('/settings/sync-now', 'POST');
+			status.textContent = `Status: synced ${result.result.files} files`;
+			lastSync.textContent = 'Last sync: ' + new Date().toLocaleString();
+		} catch (e) {
+			status.textContent = 'Status: sync failed (' + e.message + ')';
+		}
+	});
+
+	api('/settings', 'GET').then(fillForm).catch((e) => {
+		status.textContent = 'Status: failed to load settings (' + e.message + ')';
+	});
+})();
diff --git a/pocketbooksync/lib/AppInfo/Application.php b/pocketbooksync/lib/AppInfo/Application.php
new file mode 100644
index 0000000..547d051
--- /dev/null
+++ b/pocketbooksync/lib/AppInfo/Application.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\PocketBookSync\AppInfo;
+
+use OCP\AppFramework\App;
+
+class Application extends App {
+	public const APP_ID = 'pocketbooksync';
+
+	public function __construct() {
+		parent::__construct(self::APP_ID);
+	}
+}
diff --git a/pocketbooksync/lib/BackgroundJob/SyncJob.php b/pocketbooksync/lib/BackgroundJob/SyncJob.php
new file mode 100644
index 0000000..837ea8f
--- /dev/null
+++ b/pocketbooksync/lib/BackgroundJob/SyncJob.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\PocketBookSync\BackgroundJob;
+
+use OCA\PocketBookSync\Service\ConfigService;
+use OCA\PocketBookSync\Service\SyncService;
+use OCP\BackgroundJob\TimedJob;
+use OCP\IUserManager;
+use Psr\Log\LoggerInterface;
+use Throwable;
+
+class SyncJob extends TimedJob {
+	public function __construct(
+		private IUserManager $userManager,
+		private ConfigService $configService,
+		private SyncService $syncService,
+		private LoggerInterface $logger,
+	) {
+		parent::__construct();
+		$this->setInterval(300);
+	}
+
+	protected function run($argument): void {
+		foreach ($this->userManager->search('') as $user) {
+			$userId = $user->getUID();
+			$settings = $this->configService->getSettings($userId);
+			if ($settings['username'] === '' || $settings['password'] === '') {
+				continue;
+			}
+
+			if (!$this->configService->shouldSync($userId)) {
+				continue;
+			}
+
+			try {
+				$this->syncService->syncUser($userId);
+			} catch (Throwable $e) {
+				$this->configService->setLastSync($userId, 'Error: ' . $e->getMessage());
+				$this->logger->error('PocketBook background sync failed', [
+					'exception' => $e,
+					'userId' => $userId,
+				]);
+			}
+		}
+	}
+}
diff --git a/pocketbooksync/lib/Controller/SettingsController.php b/pocketbooksync/lib/Controller/SettingsController.php
new file mode 100644
index 0000000..803a405
--- /dev/null
+++ b/pocketbooksync/lib/Controller/SettingsController.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\PocketBookSync\Controller;
+
+use OCA\PocketBookSync\Service\ConfigService;
+use OCA\PocketBookSync\Service\SyncService;
+use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\AppFramework\Http\JSONResponse;
+use OCP\IRequest;
+use OCP\IUserSession;
+use Throwable;
+
+class SettingsController extends Controller {
+	private string $userId;
+
+	public function __construct(
+		string $appName,
+		IRequest $request,
+		IUserSession $userSession,
+		private ConfigService $configService,
+		private SyncService $syncService,
+	) {
+		parent::__construct($appName, $request);
+		$this->userId = $userSession->getUser()?->getUID() ?? '';
+	}
+
+	public function get(): DataResponse {
+		return new DataResponse($this->configService->getSettings($this->userId));
+	}
+
+	/** @param array<string, mixed> $payload */
+	public function save(array $payload): DataResponse {
+		$this->configService->saveSettings($this->userId, $payload);
+		return new DataResponse(['status' => 'saved']);
+	}
+
+	public function testConnection(): JSONResponse {
+		try {
+			$ok = $this->syncService->testConnection($this->userId);
+			return new JSONResponse(['ok' => $ok]);
+		} catch (Throwable $e) {
+			return new JSONResponse(['ok' => false, 'error' => $e->getMessage()], 500);
+		}
+	}
+
+	public function syncNow(): JSONResponse {
+		try {
+			$result = $this->syncService->syncUser($this->userId);
+			return new JSONResponse(['ok' => true, 'result' => $result]);
+		} catch (Throwable $e) {
+			$this->configService->setLastSync($this->userId, 'Error: ' . $e->getMessage());
+			return new JSONResponse(['ok' => false, 'error' => $e->getMessage()], 500);
+		}
+	}
+}
diff --git a/pocketbooksync/lib/Service/ConfigService.php b/pocketbooksync/lib/Service/ConfigService.php
new file mode 100644
index 0000000..dbbb32f
--- /dev/null
+++ b/pocketbooksync/lib/Service/ConfigService.php
@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\PocketBookSync\Service;
+
+use OCA\PocketBookSync\AppInfo\Application;
+use OCP\IConfig;
+
+class ConfigService {
+	public const KEY_BASE_URL = 'base_url';
+	public const KEY_USERNAME = 'username';
+	public const KEY_PASSWORD = 'password';
+	public const KEY_TARGET_FOLDER = 'target_folder';
+	public const KEY_SYNC_INTERVAL_MIN = 'sync_interval_min';
+	public const KEY_LAST_SYNC = 'last_sync';
+	public const KEY_LAST_STATUS = 'last_status';
+
+	public function __construct(private IConfig $config) {
+	}
+
+	/** @return array<string, mixed> */
+	public function getSettings(string $userId): array {
+		return [
+			'baseUrl' => $this->getUserValue($userId, self::KEY_BASE_URL, 'https://cloud.pocketbook.digital'),
+			'username' => $this->getUserValue($userId, self::KEY_USERNAME, ''),
+			'password' => $this->getUserValue($userId, self::KEY_PASSWORD, ''),
+			'targetFolder' => $this->getUserValue($userId, self::KEY_TARGET_FOLDER, '/PocketBook Highlights'),
+			'syncIntervalMin' => (int)$this->getUserValue($userId, self::KEY_SYNC_INTERVAL_MIN, '60'),
+			'lastSync' => $this->getUserValue($userId, self::KEY_LAST_SYNC, ''),
+			'lastStatus' => $this->getUserValue($userId, self::KEY_LAST_STATUS, 'Never synced'),
+		];
+	}
+
+	/** @param array<string, mixed> $payload */
+	public function saveSettings(string $userId, array $payload): void {
+		$this->setUserValue($userId, self::KEY_BASE_URL, rtrim((string)($payload['baseUrl'] ?? ''), '/'));
+		$this->setUserValue($userId, self::KEY_USERNAME, (string)($payload['username'] ?? ''));
+		$this->setUserValue($userId, self::KEY_PASSWORD, (string)($payload['password'] ?? ''));
+		$this->setUserValue($userId, self::KEY_TARGET_FOLDER, (string)($payload['targetFolder'] ?? '/PocketBook Highlights'));
+		$this->setUserValue($userId, self::KEY_SYNC_INTERVAL_MIN, (string)max(5, (int)($payload['syncIntervalMin'] ?? 60)));
+	}
+
+	public function setLastSync(string $userId, string $status): void {
+		$this->setUserValue($userId, self::KEY_LAST_SYNC, (string)time());
+		$this->setUserValue($userId, self::KEY_LAST_STATUS, $status);
+	}
+
+	public function shouldSync(string $userId): bool {
+		$settings = $this->getSettings($userId);
+		$interval = max(5, (int)$settings['syncIntervalMin']);
+		$lastSync = (int)$settings['lastSync'];
+		if ($lastSync === 0) {
+			return true;
+		}
+
+		return (time() - $lastSync) >= ($interval * 60);
+	}
+
+	private function getUserValue(string $userId, string $key, string $default): string {
+		return $this->config->getUserValue($userId, Application::APP_ID, $key, $default);
+	}
+
+	private function setUserValue(string $userId, string $key, string $value): void {
+		$this->config->setUserValue($userId, Application::APP_ID, $key, $value);
+	}
+}
diff --git a/pocketbooksync/lib/Service/PocketBookClient.php b/pocketbooksync/lib/Service/PocketBookClient.php
new file mode 100644
index 0000000..18834db
--- /dev/null
+++ b/pocketbooksync/lib/Service/PocketBookClient.php
@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\PocketBookSync\Service;
+
+use OCP\Http\Client\IClientService;
+
+class PocketBookClient {
+	public function __construct(
+		private IClientService $clientService,
+	) {
+	}
+
+	/** @param array<string, mixed> $settings */
+	public function testConnection(array $settings): bool {
+		$token = $this->authenticate($settings);
+		return $token !== '';
+	}
+
+	/**
+	 * @param array<string, mixed> $settings
+	 * @return array<int, array<string, mixed>>
+	 */
+	public function fetchBooksWithAnnotations(array $settings): array {
+		$token = $this->authenticate($settings);
+		$client = $this->clientService->newClient();
+		$response = $client->get($settings['baseUrl'] . '/api/v1/library/books', [
+			'headers' => [
+				'Authorization' => 'Bearer ' . $token,
+				'Accept' => 'application/json',
+			],
+			'query' => [
+				'includeAnnotations' => 'true',
+			],
+			'timeout' => 30,
+		]);
+
+		$payload = json_decode($response->getBody(), true, flags: JSON_THROW_ON_ERROR);
+		return $payload['books'] ?? [];
+	}
+
+	/** @param array<string, mixed> $settings */
+	private function authenticate(array $settings): string {
+		$client = $this->clientService->newClient();
+		$response = $client->post($settings['baseUrl'] . '/api/v1/auth/login', [
+			'headers' => [
+				'Accept' => 'application/json',
+			],
+			'json' => [
+				'email' => $settings['username'],
+				'password' => $settings['password'],
+			],
+			'timeout' => 30,
+		]);
+
+		$payload = json_decode($response->getBody(), true, flags: JSON_THROW_ON_ERROR);
+		return (string)($payload['token'] ?? '');
+	}
+}
diff --git a/pocketbooksync/lib/Service/SyncService.php b/pocketbooksync/lib/Service/SyncService.php
new file mode 100644
index 0000000..b7343ff
--- /dev/null
+++ b/pocketbooksync/lib/Service/SyncService.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\PocketBookSync\Service;
+
+use OCP\Files\IRootFolder;
+use OCP\Files\NotFoundException;
+
+class SyncService {
+	public function __construct(
+		private ConfigService $configService,
+		private PocketBookClient $client,
+		private IRootFolder $rootFolder,
+	) {
+	}
+
+	public function testConnection(string $userId): bool {
+		$settings = $this->configService->getSettings($userId);
+		return $this->client->testConnection($settings);
+	}
+
+	/** @return array{books:int, files:int} */
+	public function syncUser(string $userId): array {
+		$settings = $this->configService->getSettings($userId);
+		$books = $this->client->fetchBooksWithAnnotations($settings);
+		$userFolder = $this->rootFolder->getUserFolder($userId);
+		$targetFolderPath = trim((string)$settings['targetFolder']);
+		if ($targetFolderPath === '') {
+			$targetFolderPath = '/PocketBook Highlights';
+		}
+
+		try {
+			$targetFolder = $userFolder->get($targetFolderPath);
+		} catch (NotFoundException) {
+			$targetFolder = $userFolder->newFolder($targetFolderPath);
+		}
+
+		$written = 0;
+		foreach ($books as $book) {
+			$title = trim((string)($book['title'] ?? 'Unknown Title'));
+			$author = trim((string)($book['author'] ?? 'Unknown Author'));
+			$annotations = $book['annotations'] ?? [];
+			$filename = $this->toSafeFilename($title . ' - ' . $author) . '.md';
+			$contents = $this->renderBookMarkdown($title, $author, $annotations);
+
+			if ($targetFolder->nodeExists($filename)) {
+				$file = $targetFolder->get($filename);
+				$file->putContent($contents);
+			} else {
+				$targetFolder->newFile($filename, $contents);
+			}
+			$written++;
+		}
+
+		$this->configService->setLastSync($userId, sprintf('OK: synced %d books', $written));
+		return ['books' => count($books), 'files' => $written];
+	}
+
+	/** @param array<int, array<string, mixed>> $annotations */
+	private function renderBookMarkdown(string $title, string $author, array $annotations): string {
+		$lines = [
+			'# ' . $title,
+			'',
+			'- Author: ' . $author,
+			'- Synced at: ' . gmdate(DATE_ATOM),
+			'',
+			'## Highlights & Notes',
+			'',
+		];
+
+		foreach ($annotations as $annotation) {
+			$type = (string)($annotation['type'] ?? 'highlight');
+			$text = trim((string)($annotation['text'] ?? ''));
+			$note = trim((string)($annotation['note'] ?? ''));
+			$location = (string)($annotation['location'] ?? '');
+			if ($text === '' && $note === '') {
+				continue;
+			}
+
+			$lines[] = '### ' . ucfirst($type) . ($location !== '' ? ' @ ' . $location : '');
+			if ($text !== '') {
+				$lines[] = '> ' . str_replace("\n", "\n> ", $text);
+			}
+			if ($note !== '') {
+				$lines[] = '';
+				$lines[] = '- Note: ' . $note;
+			}
+			$lines[] = '';
+		}
+
+		return implode("\n", $lines) . "\n";
+	}
+
+	private function toSafeFilename(string $name): string {
+		$name = preg_replace('/[\\\\\/:*?"<>|]+/', '_', $name) ?? $name;
+		$name = preg_replace('/\s+/', ' ', $name) ?? $name;
+		return trim($name);
+	}
+}
diff --git a/pocketbooksync/lib/Settings/Personal.php b/pocketbooksync/lib/Settings/Personal.php
new file mode 100644
index 0000000..3cdb15c
--- /dev/null
+++ b/pocketbooksync/lib/Settings/Personal.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\PocketBookSync\Settings;
+
+use OCP\AppFramework\Http\TemplateResponse;
+use OCP\IL10N;
+use OCP\Settings\ISettings;
+
+class Personal implements ISettings {
+	public function __construct(
+		private IL10N $l10n,
+	) {
+	}
+
+	public function getForm(): TemplateResponse {
+		return new TemplateResponse('pocketbooksync', 'settings');
+	}
+
+	public function getSection(): string {
+		return 'additional';
+	}
+
+	public function getPriority(): int {
+		return 50;
+	}
+}
diff --git a/pocketbooksync/templates/settings.php b/pocketbooksync/templates/settings.php
new file mode 100644
index 0000000..bfa48d5
--- /dev/null
+++ b/pocketbooksync/templates/settings.php
@@ -0,0 +1,37 @@
+<?php
+script('pocketbooksync', 'settings');
+?>
+<div id="pocketbooksync-settings" class="section">
+	<h2>PocketBook Sync</h2>
+	<p>Configure your PocketBook Cloud credentials and sync target.</p>
+
+	<div class="form-group">
+		<label for="pbs-base-url">PocketBook Cloud URL</label>
+		<input id="pbs-base-url" type="url" placeholder="https://cloud.pocketbook.digital" />
+	</div>
+	<div class="form-group">
+		<label for="pbs-username">Email / Username</label>
+		<input id="pbs-username" type="text" />
+	</div>
+	<div class="form-group">
+		<label for="pbs-password">Password</label>
+		<input id="pbs-password" type="password" />
+	</div>
+	<div class="form-group">
+		<label for="pbs-target-folder">Target folder in your Nextcloud files</label>
+		<input id="pbs-target-folder" type="text" placeholder="/PocketBook Highlights" />
+	</div>
+	<div class="form-group">
+		<label for="pbs-sync-interval">Sync interval (minutes)</label>
+		<input id="pbs-sync-interval" type="number" min="5" step="1" />
+	</div>
+
+	<div class="form-actions">
+		<button id="pbs-save" class="primary">Save settings</button>
+		<button id="pbs-test">Test connection</button>
+		<button id="pbs-sync">Sync now</button>
+	</div>
+
+	<p id="pbs-status">Status: unknown</p>
+	<p id="pbs-last-sync">Last sync: never</p>
+</div>