diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..fb432f3
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,47 @@
+# SPDX-FileCopyrightText: 2026 STRATO GmbH
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+# PHP files
+[*.php]
+indent_style = tab
+indent_size = 4
+
+# JSON files
+[*.json]
+indent_style = space
+indent_size = 2
+
+# YAML files
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2
+
+# XML files
+[*.xml]
+indent_style = tab
+indent_size = 4
+
+# Markdown files
+[*.md]
+trim_trailing_whitespace = false
+
+# Shell scripts
+[*.sh]
+indent_style = tab
+indent_size = 4
+
+# Makefile
+[Makefile]
+indent_style = tab
diff --git a/README.md b/README.md
index 9bb359e..a692717 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,22 @@ NCW Tools enhances Nextcloud with advanced system utilities including event list
    php occ app:enable ncw_tools
    ```
 
+## Configuration
+
+### Post-Installation Job Retry Interval
+
+The app includes a background job that sends a welcome email to the admin user after installation. You can configure how often this job retries by setting the following system configuration value in your `config/config.php`:
+
+```php
+'ncw_tools.post_setup_job.retry_interval' => 5, // Retry every 5 seconds (default: 2)
+```
+
+**Configuration Options:**
+- **Key:** `ncw_tools.post_setup_job.retry_interval`
+- **Type:** Integer (seconds)
+- **Default:** `2` seconds
+- **Description:** Interval in seconds between retry attempts for the post-installation welcome email job
+
 ## Development
 
 ### Prerequisites
diff --git a/composer.json b/composer.json
index 57525de..31a83f0 100644
--- a/composer.json
+++ b/composer.json
@@ -14,6 +14,11 @@
 			"OCA\\NcwTools\\": "lib/"
 		}
 	},
+	"autoload-dev": {
+		"classmap": [
+			"tests/stubs/"
+		]
+	},
 	"scripts": {
 		"post-install-cmd": [
 			"@composer bin all install --ansi"
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index 28290cf..a8c6535 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -9,23 +9,22 @@
 
 namespace OCA\NcwTools\AppInfo;
 
+use OCA\NcwTools\Listeners\InstallationCompletedEventListener;
 use OCP\AppFramework\App;
 use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IBootstrap;
 use OCP\AppFramework\Bootstrap\IRegistrationContext;
+use OCP\Install\Events\InstallationCompletedEvent;
 
-/**
- * @psalm-suppress UnusedClass
- */
 class Application extends App implements IBootstrap {
 	public const APP_ID = 'ncw_tools';
 
-	/** @psalm-suppress PossiblyUnusedMethod */
 	public function __construct() {
 		parent::__construct(self::APP_ID);
 	}
 
 	public function register(IRegistrationContext $context): void {
+		$context->registerEventListener(InstallationCompletedEvent::class, InstallationCompletedEventListener::class);
 	}
 
 	public function boot(IBootContext $context): void {
diff --git a/lib/BackgroundJob/PostSetupJob.php b/lib/BackgroundJob/PostSetupJob.php
new file mode 100644
index 0000000..1f09855
--- /dev/null
+++ b/lib/BackgroundJob/PostSetupJob.php
@@ -0,0 +1,162 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 STRATO GmbH
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCA\NcwTools\BackgroundJob;
+
+use OCA\NcwTools\AppInfo\Application;
+use OCA\NcwTools\Helper\WelcomeMailHelper;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJob;
+use OCP\BackgroundJob\IJobList;
+use OCP\BackgroundJob\TimedJob;
+use OCP\Http\Client\IClient;
+use OCP\Http\Client\IClientService;
+use OCP\IAppConfig;
+use OCP\IConfig;
+use OCP\IUserManager;
+use Psr\Log\LoggerInterface;
+
+class PostSetupJob extends TimedJob {
+	public const JOB_STATUS_INIT = 'INIT';
+	public const JOB_STATUS_DONE = 'DONE';
+	public const JOB_STATUS_UNKNOWN = 'UNKNOWN';
+	public const JOB_STATUS_CONFIG_KEY = 'post_install';
+
+	public function __construct(
+		private LoggerInterface $logger,
+		private IAppConfig $appConfig,
+		private IConfig $config,
+		private IUserManager $userManager,
+		private IClientService $clientService,
+		ITimeFactory $timeFactory,
+		private IJobList $jobList,
+		private WelcomeMailHelper $welcomeMailHelper,
+	) {
+		parent::__construct($timeFactory);
+		$retryInterval = $this->config->getSystemValueInt('ncw_tools.post_setup_job.retry_interval', 2);
+		$this->setInterval($retryInterval);
+		$this->setTimeSensitivity(IJob::TIME_SENSITIVE);
+		$this->logger->debug('PostSetupJob initialized', [
+			'retryInterval' => $retryInterval,
+			'timeSensitivity' => 'TIME_SENSITIVE',
+		]);
+	}
+
+	/**
+	 * Execute the post-installation job
+	 *
+	 * Checks if the job has already completed and sends the initial welcome email
+	 * to the admin user. The job will retry until successful or marked as done.
+	 *
+	 * @param mixed $argument The admin user ID as a string
+	 */
+	protected function run($argument): void {
+		// string post install variable
+		// used to check if job has already run
+		$jobStatus = $this->appConfig->getValueString(Application::APP_ID, self::JOB_STATUS_CONFIG_KEY, self::JOB_STATUS_UNKNOWN);
+		if ($jobStatus === self::JOB_STATUS_DONE) {
+			$this->logger->info('Post-installation job already completed, removing from queue');
+			$this->jobList->remove($this);
+			return;
+		}
+
+		if ($jobStatus === self::JOB_STATUS_UNKNOWN) {
+			$this->logger->warning('Job status unknown, waiting for initialization');
+			return;
+		}
+
+		$initAdminId = (string)$argument;
+		$this->logger->info('Starting post-installation job', ['adminUserId' => $initAdminId]);
+		$this->sendInitialWelcomeMail($initAdminId);
+		$this->logger->info('Post-installation job completed', ['adminUserId' => $initAdminId]);
+	}
+
+	/**
+	 * Send initial welcome email to the admin user
+	 *
+	 * Validates system URL configuration, checks URL availability, verifies user exists,
+	 * and sends the welcome email with a password reset token. On success, marks the job
+	 * as done and removes it from the queue. Failures are logged and will trigger a retry.
+	 *
+	 * @param string $adminUserId The admin user ID to send the welcome email to
+	 */
+	protected function sendInitialWelcomeMail(string $adminUserId): void {
+		$client = $this->clientService->newClient();
+		$overwriteUrl = (string)$this->config->getSystemValue('overwrite.cli.url');
+
+		if (empty($overwriteUrl)) {
+			$this->logger->warning('System URL not configured, cannot send welcome email', [
+				'adminUserId' => $adminUserId,
+				'config_key' => 'overwrite.cli.url',
+			]);
+			return;
+		}
+
+		if (! $this->isUrlAvailable($client, $overwriteUrl)) {
+			$this->logger->info('System not ready, will retry sending welcome email', [
+				'adminUserId' => $adminUserId,
+				'url' => $overwriteUrl,
+			]);
+			return;
+		}
+		if (! $this->userManager->userExists($adminUserId)) {
+			$this->logger->warning('Admin user not found, cannot send welcome email', [
+				'adminUserId' => $adminUserId,
+			]);
+			return;
+		}
+
+		$initAdminUser = $this->userManager->get($adminUserId);
+		if ($initAdminUser === null) {
+			$this->logger->error('Failed to retrieve admin user, will retry', [
+				'adminUserId' => $adminUserId,
+			]);
+			return;
+		}
+
+		try {
+			$this->welcomeMailHelper->sendWelcomeMail($initAdminUser, true);
+		} catch (\Throwable $e) {
+			$this->logger->error('Failed to send welcome email, will retry', [
+				'adminUserId' => $adminUserId,
+				'exception' => $e->getMessage(),
+			]);
+			return;
+		}
+
+		$this->appConfig->setValueString(Application::APP_ID, self::JOB_STATUS_CONFIG_KEY, self::JOB_STATUS_DONE);
+		$this->jobList->remove($this);
+	}
+
+	/**
+	 * Check if the system URL is accessible
+	 *
+	 * Performs an HTTP GET request to the status.php endpoint to verify the system
+	 * is ready. Returns true if the response status code is in the 2xx range.
+	 *
+	 * @param IClient $client The HTTP client to use for the request
+	 * @param string $baseUrl The base URL to check (e.g., https://example.com)
+	 * @return bool True if the URL is accessible, false otherwise
+	 */
+	private function isUrlAvailable(IClient $client, string $baseUrl): bool {
+		$url = $baseUrl . '/status.php';
+		try {
+			$this->logger->debug('Checking URL availability', ['url' => $url]);
+			$response = $client->get($url);
+			$statusCode = $response->getStatusCode();
+			return $statusCode >= 200 && $statusCode < 300;
+		} catch (\Exception $ex) {
+			$this->logger->info('URL not yet accessible', [
+				'url' => $url,
+				'exception' => $ex->getMessage(),
+			]);
+			return false;
+		}
+	}
+}
diff --git a/lib/Helper/WelcomeMailHelper.php b/lib/Helper/WelcomeMailHelper.php
new file mode 100644
index 0000000..0d23031
--- /dev/null
+++ b/lib/Helper/WelcomeMailHelper.php
@@ -0,0 +1,67 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 STRATO GmbH
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCA\NcwTools\Helper;
+
+use OCA\Settings\Mailer\NewUserMailHelper;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\Defaults;
+use OCP\IConfig;
+use OCP\IURLGenerator;
+use OCP\IUser;
+use OCP\L10N\IFactory;
+use OCP\Mail\IMailer;
+use OCP\Security\ICrypto;
+use OCP\Security\ISecureRandom;
+use OCP\Util;
+
+class WelcomeMailHelper {
+	public function __construct(
+		private Defaults $defaults,
+		private ICrypto $crypto,
+		private IMailer $mailer,
+		private IURLGenerator $urlGenerator,
+		private IFactory $l10NFactory,
+		private ISecureRandom $secureRandom,
+		private IConfig $config,
+		private ITimeFactory $timeFactory,
+	) {
+	}
+
+	/**
+	 * Send a welcome email to a user with optional password reset token
+	 *
+	 * Creates a NewUserMailHelper instance and uses it to generate and send
+	 * the welcome email template to the specified user.
+	 *
+	 * @param IUser $user The user to send the welcome email to
+	 * @param bool $generatePasswordResetToken Whether to include a password reset token in the email
+	 * @throws \Exception If email generation or sending fails
+	 */
+	public function sendWelcomeMail(IUser $user, bool $generatePasswordResetToken): void {
+		$newUserMailHelper = new NewUserMailHelper(
+			$this->defaults,
+			$this->urlGenerator,
+			$this->l10NFactory,
+			$this->mailer,
+			$this->secureRandom,
+			$this->timeFactory,
+			$this->config,
+			$this->crypto,
+			Util::getDefaultEmailAddress('no-reply')
+		);
+
+		$mailTmpl = $newUserMailHelper->generateTemplate($user, $generatePasswordResetToken);
+		if ($mailTmpl === null) {
+			// User has no email address, cannot send welcome mail
+			return;
+		}
+		$newUserMailHelper->sendMail($user, $mailTmpl);
+	}
+}
diff --git a/lib/Listeners/InstallationCompletedEventListener.php b/lib/Listeners/InstallationCompletedEventListener.php
new file mode 100644
index 0000000..0da1374
--- /dev/null
+++ b/lib/Listeners/InstallationCompletedEventListener.php
@@ -0,0 +1,58 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 STRATO GmbH
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCA\NcwTools\Listeners;
+
+use OCA\NcwTools\AppInfo\Application;
+use OCA\NcwTools\BackgroundJob\PostSetupJob;
+use OCP\BackgroundJob\IJobList;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use OCP\IAppConfig;
+use OCP\Install\Events\InstallationCompletedEvent;
+use Psr\Log\LoggerInterface;
+
+/**
+ * @template-implements IEventListener<InstallationCompletedEvent>
+ */
+class InstallationCompletedEventListener implements IEventListener {
+
+	public function __construct(
+		private IAppConfig $appConfig,
+		private LoggerInterface $logger,
+		private IJobList $jobList,
+	) {
+	}
+
+	/**
+	 * Handle the InstallationCompletedEvent
+	 *
+	 * When installation completes, this listener schedules a PostSetupJob
+	 * to send the initial welcome email to the admin user.
+	 *
+	 * @param Event $event The event to handle (must be InstallationCompletedEvent)
+	 */
+	public function handle(Event $event): void {
+		if (!$event instanceof InstallationCompletedEvent) {
+			return;
+		}
+
+		$this->appConfig->setValueString(Application::APP_ID, PostSetupJob::JOB_STATUS_CONFIG_KEY, PostSetupJob::JOB_STATUS_INIT);
+
+		$adminUserId = $event->getAdminUsername();
+		if ($adminUserId === null) {
+			$this->logger->warning('No admin user provided in InstallationCompletedEvent');
+			return;
+		}
+
+		$this->logger->info('Scheduling welcome email job', ['adminUserId' => $adminUserId]);
+		$this->jobList->add(PostSetupJob::class, $adminUserId);
+		$this->logger->debug('Welcome email job scheduled successfully', ['adminUserId' => $adminUserId]);
+	}
+}
diff --git a/psalm-baseline.xml b/psalm-baseline.xml
new file mode 100644
index 0000000..08c77e3
--- /dev/null
+++ b/psalm-baseline.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  - SPDX-FileCopyrightText: 2026 STRATO GmbH
+  - SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+<files psalm-version="5.26.1@d747f6500b38ac4f7dfc5edbcae6e4b637d7add0"/>
diff --git a/psalm.xml b/psalm.xml
index e2853b7..6f28d5e 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -1,21 +1,38 @@
 <?xml version="1.0"?>
 <psalm
-    errorLevel="1"
-    resolveFromConfigFile="true"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xmlns="https://getpsalm.org/schema/config"
-    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
-    findUnusedBaselineEntry="true"
-    findUnusedCode="true"
+	errorLevel="1"
+	resolveFromConfigFile="true"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns="https://getpsalm.org/schema/config"
+	xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+	findUnusedBaselineEntry="true"
+	findUnusedCode="true"
 	phpVersion="8.1"
+	errorBaseline="psalm-baseline.xml"
 >
-    <projectFiles>
-        <directory name="lib" />
-        <ignoreFiles>
-            <directory name="vendor" />
-        </ignoreFiles>
-    </projectFiles>
+	<projectFiles>
+		<directory name="lib"/>
+		<ignoreFiles>
+			<directory name="vendor"/>
+		</ignoreFiles>
+	</projectFiles>
 	<extraFiles>
 		<directory name="vendor"/>
+		<directory name="tests/stubs"/>
 	</extraFiles>
+	<issueHandlers>
+		<UnusedClass>
+			<errorLevel type="suppress">
+				<referencedClass name="OCA\NcwTools\AppInfo\Application" />
+			</errorLevel>
+		</UnusedClass>
+		<PossiblyUnusedMethod>
+			<errorLevel type="suppress">
+				<referencedMethod name="OCA\NcwTools\AppInfo\Application::__construct" />
+				<referencedMethod name="OCA\NcwTools\BackgroundJob\PostSetupJob::__construct" />
+				<referencedMethod name="OCA\NcwTools\Helper\WelcomeMailHelper::__construct" />
+				<referencedMethod name="OCA\NcwTools\Listeners\InstallationCompletedEventListener::__construct" />
+			</errorLevel>
+		</PossiblyUnusedMethod>
+	</issueHandlers>
 </psalm>
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 22f6d85..ba147cc 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -10,5 +10,14 @@
 require_once __DIR__ . '/../../../tests/bootstrap.php';
 require_once __DIR__ . '/../vendor/autoload.php';
 
+// Autoload test stubs for classes not available in the current OCP package
+spl_autoload_register(function ($class) {
+	$stubsDir = __DIR__ . '/stubs/';
+	$file = $stubsDir . str_replace('\\', '/', $class) . '.php';
+	if (file_exists($file)) {
+		require_once $file;
+	}
+});
+
 \OC_App::loadApp(OCA\NcwTools\AppInfo\Application::APP_ID);
 OC_Hook::clear();
diff --git a/tests/stubs/OCA/Settings/Mailer/NewUserMailHelper.php b/tests/stubs/OCA/Settings/Mailer/NewUserMailHelper.php
new file mode 100644
index 0000000..576fddd
--- /dev/null
+++ b/tests/stubs/OCA/Settings/Mailer/NewUserMailHelper.php
@@ -0,0 +1,99 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 STRATO GmbH
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * Stub based on Nextcloud server stable31
+ * https://github.com/nextcloud/server/blob/stable31/apps/settings/lib/Mailer/NewUserMailHelper.php
+ */
+
+declare(strict_types=1);
+
+namespace OCA\Settings\Mailer;
+
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\Defaults;
+use OCP\IConfig;
+use OCP\IURLGenerator;
+use OCP\IUser;
+use OCP\L10N\IFactory;
+use OCP\Mail\IEMailTemplate;
+use OCP\Mail\IMailer;
+use OCP\Security\ICrypto;
+use OCP\Security\ISecureRandom;
+
+class NewUserMailHelper {
+	/**
+	 * @param Defaults $themingDefaults
+	 * @param IURLGenerator $urlGenerator
+	 * @param IFactory $l10nFactory
+	 * @param IMailer $mailer
+	 * @param ISecureRandom $secureRandom
+	 * @param ITimeFactory $timeFactory
+	 * @param IConfig $config
+	 * @param ICrypto $crypto
+	 * @param string $fromAddress
+	 */
+	public function __construct(
+		private Defaults $themingDefaults,
+		private IURLGenerator $urlGenerator,
+		private IFactory $l10nFactory,
+		private IMailer $mailer,
+		private ISecureRandom $secureRandom,
+		private ITimeFactory $timeFactory,
+		private IConfig $config,
+		private ICrypto $crypto,
+		private $fromAddress,
+	) {
+	}
+
+	/**
+	 * @param IUser $user
+	 * @param bool $generatePasswordResetToken
+	 * @return IEMailTemplate|null
+	 */
+	public function generateTemplate(IUser $user, $generatePasswordResetToken = false): ?IEMailTemplate {
+		// Return null if user has no email address (stub behavior)
+		if ($user->getEMailAddress() === null) {
+			return null;
+		}
+
+		$userId = $user->getUID();
+
+		if ($generatePasswordResetToken) {
+			$token = $this->secureRandom->generate(
+				21,
+				ISecureRandom::CHAR_ALPHANUMERIC
+			);
+			$tokenValue = $this->timeFactory->getTime() . ':' . $token;
+			$mailAddress = ($user->getEMailAddress() !== null) ? $user->getEMailAddress() : '';
+			$encryptedValue = $this->crypto->encrypt($tokenValue, $mailAddress . $this->config->getSystemValue('secret'));
+			$this->config->setUserValue($user->getUID(), 'core', 'lostpassword', $encryptedValue);
+		}
+
+		// Return a mock email template
+		return $this->mailer->createEMailTemplate('settings.Welcome');
+	}
+
+	/**
+	 * Sends a welcome mail to $user
+	 *
+	 * @param IUser $user
+	 * @param IEMailTemplate $emailTemplate
+	 * @throws \Exception If mail could not be sent
+	 */
+	public function sendMail(IUser $user, IEMailTemplate $emailTemplate): void {
+		// Return early if user has no email (stub behavior)
+		if ($user->getEMailAddress() === null) {
+			return;
+		}
+
+		// Simulate sending the mail
+		$message = $this->mailer->createMessage();
+		$message->setTo([$user->getEMailAddress() => $user->getDisplayName()]);
+		$message->setFrom([$this->fromAddress => $this->themingDefaults->getName()]);
+		$message->useTemplate($emailTemplate);
+		$this->mailer->send($message);
+	}
+}
diff --git a/tests/stubs/OCP/Install/Events/InstallationCompletedEvent.php b/tests/stubs/OCP/Install/Events/InstallationCompletedEvent.php
new file mode 100644
index 0000000..604cc03
--- /dev/null
+++ b/tests/stubs/OCP/Install/Events/InstallationCompletedEvent.php
@@ -0,0 +1,67 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 STRATO GmbH
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCP\Install\Events;
+
+use OCP\EventDispatcher\Event;
+
+/**
+ * Mock class for InstallationCompletedEvent
+ * This is a stub for testing purposes when the actual class is not available in the OCP package
+ *
+ * @since 33.0.0
+ */
+class InstallationCompletedEvent extends Event {
+	/**
+	 * @since 33.0.0
+	 */
+	public function __construct(
+		private string $dataDirectory,
+		private ?string $adminUsername = null,
+		private ?string $adminEmail = null,
+	) {
+		parent::__construct();
+	}
+
+	/**
+	 * Get the configured data directory path
+	 *
+	 * @since 33.0.0
+	 */
+	public function getDataDirectory(): string {
+		return $this->dataDirectory;
+	}
+
+	/**
+	 * Get the admin username if an admin user was created
+	 *
+	 * @since 33.0.0
+	 */
+	public function getAdminUsername(): ?string {
+		return $this->adminUsername;
+	}
+
+	/**
+	 * Get the admin email if configured
+	 *
+	 * @since 33.0.0
+	 */
+	public function getAdminEmail(): ?string {
+		return $this->adminEmail;
+	}
+
+	/**
+	 * Check if an admin user was created during installation
+	 *
+	 * @since 33.0.0
+	 */
+	public function hasAdminUser(): bool {
+		return $this->adminUsername !== null;
+	}
+}
diff --git a/tests/unit/AppInfo/ApplicationTest.php b/tests/unit/AppInfo/ApplicationTest.php
index ccde177..1207977 100644
--- a/tests/unit/AppInfo/ApplicationTest.php
+++ b/tests/unit/AppInfo/ApplicationTest.php
@@ -10,8 +10,10 @@
 namespace OCA\NcwTools\Tests\Unit\AppInfo;
 
 use OCA\NcwTools\AppInfo\Application;
+use OCA\NcwTools\Listeners\InstallationCompletedEventListener;
 use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IRegistrationContext;
+use OCP\Install\Events\InstallationCompletedEvent;
 use PHPUnit\Framework\MockObject\MockObject;
 use Test\TestCase;
 
@@ -37,9 +39,15 @@ public function testConstructorInitializesWithCorrectAppId(): void {
 	}
 
 	public function testRegisterMethodExists(): void {
-		// Test that register method can be called without errors
-		// Since the method is currently empty, we just verify it doesn't throw
-		$this->expectNotToPerformAssertions();
+		// Test that register method registers the InstallationCompletedEvent listener
+		$this->registrationContext
+			->expects($this->once())
+			->method('registerEventListener')
+			->with(
+				InstallationCompletedEvent::class,
+				InstallationCompletedEventListener::class
+			);
+
 		$this->application->register($this->registrationContext);
 	}
 }
diff --git a/tests/unit/BackgroundJob/PostSetupJobTest.php b/tests/unit/BackgroundJob/PostSetupJobTest.php
new file mode 100644
index 0000000..dbb1ef6
--- /dev/null
+++ b/tests/unit/BackgroundJob/PostSetupJobTest.php
@@ -0,0 +1,318 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 STRATO GmbH
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCA\NcwTools\Tests\Unit\BackgroundJob;
+
+use OCA\NcwTools\BackgroundJob\PostSetupJob;
+use OCA\NcwTools\Helper\WelcomeMailHelper;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJobList;
+use OCP\Http\Client\IClient;
+use OCP\Http\Client\IClientService;
+use OCP\Http\Client\IResponse;
+use OCP\IAppConfig;
+use OCP\IConfig;
+use OCP\IUser;
+use OCP\IUserManager;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Log\LoggerInterface;
+use Test\TestCase;
+
+class PostSetupJobTest extends TestCase {
+	private LoggerInterface&MockObject $logger;
+	private IAppConfig&MockObject $appConfig;
+	private IConfig&MockObject $config;
+	private IUserManager&MockObject $userManager;
+	private IClientService&MockObject $clientService;
+	private ITimeFactory&MockObject $timeFactory;
+	private IJobList&MockObject $jobList;
+	private WelcomeMailHelper&MockObject $welcomeMailHelper;
+	private PostSetupJob $job;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->logger = $this->createMock(LoggerInterface::class);
+		$this->appConfig = $this->createMock(IAppConfig::class);
+		$this->config = $this->createMock(IConfig::class);
+		$this->userManager = $this->createMock(IUserManager::class);
+		$this->clientService = $this->createMock(IClientService::class);
+		$this->timeFactory = $this->createMock(ITimeFactory::class);
+		$this->jobList = $this->createMock(IJobList::class);
+		$this->welcomeMailHelper = $this->createMock(WelcomeMailHelper::class);
+
+		// Default config expectation for retry interval
+		$this->config->expects($this->any())
+			->method('getSystemValueInt')
+			->with('ncw_tools.post_setup_job.retry_interval', 2)
+			->willReturn(2);
+
+		// Expect debug log in constructor
+		$this->logger->expects($this->any())
+			->method('debug')
+			->willReturnCallback(function ($message, $context = []) {
+				// Allow any debug messages
+			});
+
+		$this->job = new PostSetupJob(
+			$this->logger,
+			$this->appConfig,
+			$this->config,
+			$this->userManager,
+			$this->clientService,
+			$this->timeFactory,
+			$this->jobList,
+			$this->welcomeMailHelper
+		);
+	}
+
+	public function testRunWithJobAlreadyDone(): void {
+		$this->appConfig->expects($this->once())
+			->method('getValueString')
+			->with('ncw_tools', 'post_install', 'UNKNOWN')
+			->willReturn('DONE');
+
+		$this->logger->expects($this->once())
+			->method('info')
+			->with('Post-installation job already completed, removing from queue');
+
+		// Use reflection to call protected method
+		$reflection = new \ReflectionClass($this->job);
+		$method = $reflection->getMethod('run');
+		$method->setAccessible(true);
+		$method->invoke($this->job, 'test-admin');
+	}
+
+	public function testRunWithUnknownStatus(): void {
+		$this->appConfig->expects($this->once())
+			->method('getValueString')
+			->with('ncw_tools', 'post_install', 'UNKNOWN')
+			->willReturn('UNKNOWN');
+
+		$this->logger->expects($this->once())
+			->method('warning')
+			->with('Job status unknown, waiting for initialization');
+
+		// Use reflection to call protected method
+		$reflection = new \ReflectionClass($this->job);
+		$method = $reflection->getMethod('run');
+		$method->setAccessible(true);
+		$method->invoke($this->job, 'test-admin');
+	}
+
+	public function testRunWithPendingStatus(): void {
+		$this->appConfig->expects($this->once())
+			->method('getValueString')
+			->with('ncw_tools', 'post_install', 'UNKNOWN')
+			->willReturn('PENDING');
+
+		$this->config->expects($this->once())
+			->method('getSystemValue')
+			->with('overwrite.cli.url')
+			->willReturn('https://example.com');
+
+		$client = $this->createMock(IClient::class);
+		$response = $this->createMock(IResponse::class);
+		$response->expects($this->atLeastOnce())
+			->method('getStatusCode')
+			->willReturn(200);
+
+		$client->expects($this->once())
+			->method('get')
+			->with('https://example.com/status.php')
+			->willReturn($response);
+
+		$this->clientService->expects($this->once())
+			->method('newClient')
+			->willReturn($client);
+
+		$this->userManager->expects($this->once())
+			->method('userExists')
+			->with('test-admin')
+			->willReturn(false);
+
+		// Expect info logs for job start/completion and system ready
+		$this->logger->expects($this->atLeastOnce())
+			->method('info');
+
+		$this->logger->expects($this->once())
+			->method('warning')
+			->with('Admin user not found, cannot send welcome email', $this->anything());
+
+		// setValueString should NOT be called when user doesn't exist (job will retry)
+		$this->appConfig->expects($this->never())
+			->method('setValueString');
+
+		// Use reflection to call protected method
+		$reflection = new \ReflectionClass($this->job);
+		$method = $reflection->getMethod('run');
+		$method->setAccessible(true);
+		$method->invoke($this->job, 'test-admin');
+	}
+
+	public function testRunWithUrlNotAvailable(): void {
+		$this->appConfig->expects($this->once())
+			->method('getValueString')
+			->with('ncw_tools', 'post_install', 'UNKNOWN')
+			->willReturn('PENDING');
+
+		$this->config->expects($this->once())
+			->method('getSystemValue')
+			->with('overwrite.cli.url')
+			->willReturn('https://example.com');
+
+		$client = $this->createMock(IClient::class);
+		$client->expects($this->once())
+			->method('get')
+			->with('https://example.com/status.php')
+			->willThrowException(new \Exception('Connection failed'));
+
+		$this->clientService->expects($this->once())
+			->method('newClient')
+			->willReturn($client);
+
+		// Expect info calls for:
+		// 1. "Starting post-installation job"
+		// 2. "URL not yet accessible" (from exception)
+		// 3. "System not ready, will retry sending welcome email"
+		// 4. "Post-installation job completed"
+		$this->logger->expects($this->atLeastOnce())
+			->method('info');
+
+		// Expect 1 debug call for URL checking
+		$this->logger->expects($this->once())
+			->method('debug');
+
+		$this->appConfig->expects($this->never())
+			->method('setValueString');
+
+		// Use reflection to call protected method
+		$reflection = new \ReflectionClass($this->job);
+		$method = $reflection->getMethod('run');
+		$method->setAccessible(true);
+		$method->invoke($this->job, 'test-admin');
+	}
+
+	public function testRunWithSuccessfulMailSend(): void {
+		$this->appConfig->expects($this->once())
+			->method('getValueString')
+			->with('ncw_tools', 'post_install', 'UNKNOWN')
+			->willReturn('PENDING');
+
+		$this->config->expects($this->once())
+			->method('getSystemValue')
+			->with('overwrite.cli.url')
+			->willReturn('https://example.com');
+
+		$client = $this->createMock(IClient::class);
+		$response = $this->createMock(IResponse::class);
+		$response->expects($this->atLeastOnce())
+			->method('getStatusCode')
+			->willReturn(200);
+
+		$client->expects($this->once())
+			->method('get')
+			->with('https://example.com/status.php')
+			->willReturn($response);
+
+		$this->clientService->expects($this->once())
+			->method('newClient')
+			->willReturn($client);
+
+		$user = $this->createMock(IUser::class);
+		$user->method('getUID')->willReturn('test-admin');
+		$user->method('getEMailAddress')->willReturn('admin@example.com');
+		$user->method('getBackendClassName')->willReturn('Database');
+
+		$this->userManager->expects($this->once())
+			->method('userExists')
+			->with('test-admin')
+			->willReturn(true);
+
+		$this->userManager->expects($this->once())
+			->method('get')
+			->with('test-admin')
+			->willReturn($user);
+
+		// Expect debug logs (allow flexible count due to URL checking)
+		$this->logger->expects($this->atLeastOnce())
+			->method('debug');
+
+		// Expect welcome mail to be sent
+		$this->welcomeMailHelper->expects($this->once())
+			->method('sendWelcomeMail')
+			->with($user, true);
+
+		$this->appConfig->expects($this->once())
+			->method('setValueString')
+			->with('ncw_tools', 'post_install', 'DONE');
+
+		// Use reflection to call protected method
+		$reflection = new \ReflectionClass($this->job);
+		$method = $reflection->getMethod('run');
+		$method->setAccessible(true);
+		$method->invoke($this->job, 'test-admin');
+	}
+
+	public function testConstructorUsesDefaultRetryInterval(): void {
+		$logger = $this->createMock(LoggerInterface::class);
+		$config = $this->createMock(IConfig::class);
+
+		$config->expects($this->once())
+			->method('getSystemValueInt')
+			->with('ncw_tools.post_setup_job.retry_interval', 2)
+			->willReturn(2);
+
+		$logger->expects($this->once())
+			->method('debug')
+			->with('PostSetupJob initialized', [
+				'retryInterval' => 2,
+				'timeSensitivity' => 'TIME_SENSITIVE',
+			]);
+
+		new PostSetupJob(
+			$logger,
+			$this->appConfig,
+			$config,
+			$this->userManager,
+			$this->clientService,
+			$this->timeFactory,
+			$this->jobList,
+			$this->welcomeMailHelper
+		);
+	}
+
+	public function testConstructorUsesCustomRetryInterval(): void {
+		$logger = $this->createMock(LoggerInterface::class);
+		$config = $this->createMock(IConfig::class);
+
+		$config->expects($this->once())
+			->method('getSystemValueInt')
+			->with('ncw_tools.post_setup_job.retry_interval', 2)
+			->willReturn(10);
+
+		$logger->expects($this->once())
+			->method('debug')
+			->with('PostSetupJob initialized', [
+				'retryInterval' => 10,
+				'timeSensitivity' => 'TIME_SENSITIVE',
+			]);
+
+		new PostSetupJob(
+			$logger,
+			$this->appConfig,
+			$config,
+			$this->userManager,
+			$this->clientService,
+			$this->timeFactory,
+			$this->jobList,
+			$this->welcomeMailHelper
+		);
+	}
+}
diff --git a/tests/unit/Helper/WelcomeMailHelperTest.php b/tests/unit/Helper/WelcomeMailHelperTest.php
new file mode 100644
index 0000000..ceae501
--- /dev/null
+++ b/tests/unit/Helper/WelcomeMailHelperTest.php
@@ -0,0 +1,163 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 STRATO GmbH
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCA\NcwTools\Tests\Unit\Helper;
+
+use OCA\NcwTools\Helper\WelcomeMailHelper;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\Defaults;
+use OCP\IConfig;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use OCP\IUser;
+use OCP\L10N\IFactory;
+use OCP\Mail\IEMailTemplate;
+use OCP\Mail\IMailer;
+use OCP\Mail\IMessage;
+use OCP\Security\ICrypto;
+use OCP\Security\ISecureRandom;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class WelcomeMailHelperTest extends TestCase {
+	private Defaults&MockObject $defaults;
+	private ICrypto&MockObject $crypto;
+	private IMailer&MockObject $mailer;
+	private IURLGenerator&MockObject $urlGenerator;
+	private IFactory&MockObject $l10NFactory;
+	private ISecureRandom&MockObject $secureRandom;
+	private IConfig&MockObject $config;
+	private ITimeFactory&MockObject $timeFactory;
+	private WelcomeMailHelper $welcomeMailHelper;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->defaults = $this->createMock(Defaults::class);
+		$this->crypto = $this->createMock(ICrypto::class);
+		$this->mailer = $this->createMock(IMailer::class);
+		$this->urlGenerator = $this->createMock(IURLGenerator::class);
+		$this->l10NFactory = $this->createMock(IFactory::class);
+		$this->secureRandom = $this->createMock(ISecureRandom::class);
+		$this->config = $this->createMock(IConfig::class);
+		$this->timeFactory = $this->createMock(ITimeFactory::class);
+
+		// Setup mocks required by NewUserMailHelper
+		$l10n = $this->createMock(IL10N::class);
+		$l10n->method('t')->willReturnArgument(0);
+		$this->l10NFactory->method('get')->willReturn($l10n);
+		$this->l10NFactory->method('getUserLanguage')->willReturn('en');
+
+		$emailTemplate = $this->createMock(IEMailTemplate::class);
+		$emailTemplate->method('addHeader')->willReturnSelf();
+		$emailTemplate->method('addHeading')->willReturnSelf();
+		$emailTemplate->method('addBodyText')->willReturnSelf();
+		$emailTemplate->method('addBodyButton')->willReturnSelf();
+		$emailTemplate->method('addBodyButtonGroup')->willReturnSelf();
+		$emailTemplate->method('addFooter')->willReturnSelf();
+		$emailTemplate->method('setSubject')->willReturnSelf();
+		$this->mailer->method('createEMailTemplate')->willReturn($emailTemplate);
+
+		$message = $this->createMock(IMessage::class);
+		$message->method('setTo')->willReturnSelf();
+		$message->method('setFrom')->willReturnSelf();
+		$message->method('useTemplate')->willReturnSelf();
+		$message->method('setAutoSubmitted')->willReturnSelf();
+		$this->mailer->method('createMessage')->willReturn($message);
+
+		$this->defaults->method('getName')->willReturn('Nextcloud');
+		$this->urlGenerator->method('getAbsoluteURL')->willReturn('https://example.com');
+		$this->urlGenerator->method('linkToRouteAbsolute')->willReturn('https://example.com/reset');
+		$this->secureRandom->method('generate')->willReturn('test-token');
+		$this->crypto->method('encrypt')->willReturn('encrypted-token');
+		$this->config->method('getSystemValue')->willReturnMap([
+			['customclient_desktop', 'https://nextcloud.com/install/#install-clients', 'https://nextcloud.com/install/#install-clients'],
+			['secret', '', 'test-secret'],
+		]);
+
+		$this->welcomeMailHelper = new WelcomeMailHelper(
+			$this->defaults,
+			$this->crypto,
+			$this->mailer,
+			$this->urlGenerator,
+			$this->l10NFactory,
+			$this->secureRandom,
+			$this->config,
+			$this->timeFactory
+		);
+	}
+
+	public function testSendWelcomeMailWithPasswordResetToken(): void {
+		$user = $this->createMock(IUser::class);
+		$user->method('getUID')->willReturn('testuser');
+		$user->method('getDisplayName')->willReturn('Test User');
+		$user->method('getEMailAddress')->willReturn('testuser@example.com');
+		$user->method('getBackendClassName')->willReturn('Database');
+
+		$this->timeFactory->expects($this->once())
+			->method('getTime')
+			->willReturn(1234567890);
+
+		$this->config->expects($this->once())
+			->method('setUserValue')
+			->with('testuser', 'core', 'lostpassword', $this->anything());
+
+		$this->mailer->expects($this->once())
+			->method('send');
+
+		$this->welcomeMailHelper->sendWelcomeMail($user, true);
+	}
+
+	public function testSendWelcomeMailWithoutPasswordResetToken(): void {
+		$user = $this->createMock(IUser::class);
+		$user->method('getUID')->willReturn('testuser');
+		$user->method('getDisplayName')->willReturn('Test User');
+		$user->method('getEMailAddress')->willReturn('testuser@example.com');
+		$user->method('getBackendClassName')->willReturn('Database');
+
+		$this->timeFactory->expects($this->never())
+			->method('getTime');
+
+		$this->config->expects($this->never())
+			->method('setUserValue');
+
+		$this->mailer->expects($this->once())
+			->method('send');
+
+		$this->welcomeMailHelper->sendWelcomeMail($user, false);
+	}
+
+	public function testSendWelcomeMailWithUserWithoutEmail(): void {
+		$user = $this->createMock(IUser::class);
+		$user->method('getUID')->willReturn('testuser');
+		$user->method('getDisplayName')->willReturn('Test User');
+		$user->method('getEMailAddress')->willReturn(null);
+		$user->method('getBackendClassName')->willReturn('Database');
+
+		$this->mailer->expects($this->never())
+			->method('send');
+
+		$this->welcomeMailHelper->sendWelcomeMail($user, false);
+	}
+
+	public function testConstructorInitializesCorrectly(): void {
+		$helper = new WelcomeMailHelper(
+			$this->defaults,
+			$this->crypto,
+			$this->mailer,
+			$this->urlGenerator,
+			$this->l10NFactory,
+			$this->secureRandom,
+			$this->config,
+			$this->timeFactory
+		);
+
+		$this->assertInstanceOf(WelcomeMailHelper::class, $helper);
+	}
+}
diff --git a/tests/unit/Listeners/InstallationCompletedEventListenerTest.php b/tests/unit/Listeners/InstallationCompletedEventListenerTest.php
new file mode 100644
index 0000000..84bca29
--- /dev/null
+++ b/tests/unit/Listeners/InstallationCompletedEventListenerTest.php
@@ -0,0 +1,99 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 STRATO GmbH
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OCA\NcwTools\Tests\Unit\Listeners;
+
+use OCA\NcwTools\BackgroundJob\PostSetupJob;
+use OCA\NcwTools\Listeners\InstallationCompletedEventListener;
+use OCP\BackgroundJob\IJobList;
+use OCP\EventDispatcher\Event;
+use OCP\IAppConfig;
+use OCP\Install\Events\InstallationCompletedEvent;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Log\LoggerInterface;
+use Test\TestCase;
+
+class InstallationCompletedEventListenerTest extends TestCase {
+	private IAppConfig&MockObject $appConfig;
+	private LoggerInterface&MockObject $logger;
+	private IJobList&MockObject $jobList;
+	private InstallationCompletedEventListener $listener;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->appConfig = $this->createMock(IAppConfig::class);
+		$this->logger = $this->createMock(LoggerInterface::class);
+		$this->jobList = $this->createMock(IJobList::class);
+
+		$this->listener = new InstallationCompletedEventListener(
+			$this->appConfig,
+			$this->logger,
+			$this->jobList
+		);
+	}
+
+	public function testHandleSetsAppConfigAndAddsJob(): void {
+		$event = new InstallationCompletedEvent(
+			'/var/www/html/data',
+			'admin',
+			'admin@example.com'
+		);
+
+		// Expect app config to be set for 'post_install'
+		$this->appConfig->expects($this->once())
+			->method('setValueString')
+			->with('ncw_tools', 'post_install', 'INIT');
+
+		// Expect job to be added
+		$this->jobList->expects($this->once())
+			->method('add')
+			->with(PostSetupJob::class, 'admin');
+
+		// Expect debug logs
+		$this->logger->expects($this->atLeastOnce())
+			->method('debug');
+
+		$this->listener->handle($event);
+	}
+
+	public function testHandleWithoutAdminUser(): void {
+		$event = new InstallationCompletedEvent(
+			'/var/www/html/data'
+		);
+
+		$this->appConfig->expects($this->once())
+			->method('setValueString')
+			->with('ncw_tools', 'post_install', 'INIT');
+
+		// Expect warning when no admin user
+		$this->logger->expects($this->once())
+			->method('warning')
+			->with('No admin user provided in InstallationCompletedEvent');
+
+		// Job should NOT be added
+		$this->jobList->expects($this->never())
+			->method('add');
+
+		$this->listener->handle($event);
+	}
+
+	public function testHandleWithWrongEventType(): void {
+		$event = $this->createMock(Event::class);
+
+		// Should not process non-InstallationCompletedEvent events
+		$this->appConfig->expects($this->never())
+			->method('setValueString');
+
+		$this->jobList->expects($this->never())
+			->method('add');
+
+		$this->listener->handle($event);
+	}
+}