diff --git a/snappymail/v/0.0.0/app/libraries/RainLoop/ServiceActions.php b/snappymail/v/0.0.0/app/libraries/RainLoop/ServiceActions.php
index 85aaf1c95..edad11c62 100644
--- a/snappymail/v/0.0.0/app/libraries/RainLoop/ServiceActions.php
+++ b/snappymail/v/0.0.0/app/libraries/RainLoop/ServiceActions.php
@@ -528,6 +528,13 @@ class ServiceActions
 		return 'Pong';
 	}
 
+	public function ServiceTest() : string
+	{
+		$this->oHttp->ServerNoCache();
+		\SnappyMail\Integrity::test();
+		return '';
+	}
+
 	/**
 	 * Login with the \RainLoop\API::CreateUserSsoHash() generated hash
 	 */
diff --git a/snappymail/v/0.0.0/app/libraries/snappymail/integrity.php b/snappymail/v/0.0.0/app/libraries/snappymail/integrity.php
new file mode 100644
index 000000000..90ad4ce86
--- /dev/null
+++ b/snappymail/v/0.0.0/app/libraries/snappymail/integrity.php
@@ -0,0 +1,107 @@
+<?php
+
+namespace SnappyMail;
+
+abstract class Integrity
+{
+
+	/**
+	 * Called by https://webmail.tld/?/Test
+	 */
+	public static function test()
+	{
+		$result = static::phpVersion();
+		if ($result) {
+			echo '<p style="color: red">' . $result . '</p>';
+			return;
+		}
+
+		$result = static::phpExtensions();
+		if ($result) {
+			echo '<p>The following PHP extensions are not available in your PHP configuration!</p>';
+			echo '<ul><li>' . \implode('</li>li><li>', $result) . '</li></ul>';
+		}
+
+		$uri = (isset($_SERVER['HTTPS']) ? 'https' : 'http') . '://' . $_SERVER['HTTP_HOST']
+			. \RainLoop\Utils::WebVersionPath();
+		$HTTP = \SnappyMail\HTTP\Request::factory();
+		$files = [
+//			'static/css/app.css',
+//			'static/js/libs.js',
+//			'static/js/app.js',
+//			'static/js/openpgp.js',
+			'static/css/app.min.css',
+			'static/js/min/libs.min.js',
+			'static/js/min/app.min.js',
+			'static/js/min/openpgp.min.js'
+		];
+		foreach ($files as $file) {
+			echo "<h2>{$uri}{$file}</h2>";
+			$response = $HTTP->doRequest('HEAD', $uri . $file);
+			echo '<details><summary>Status: ' . $response->status . '</summary><pre>' . \print_r($response->headers, 1) . '</pre></details>';
+			$size = \filesize(APP_VERSION_ROOT_PATH.$file);
+			if ($size == intval($response->getHeader('content-length'))) {
+				echo 'content-length matches size ' . $size;
+			} else {
+				echo 'content-length mismatch, should be ' . $size;
+			}
+/*
+			echo "<h3>encoding</h3>";
+			$response = $HTTP->doRequest('GET', $uri . $file, null, ['Accept-Encoding' => 'gzip, deflate, br']);
+			echo '<details><summary>Status: ' . $response->status . '</summary><pre>' . \print_r($response->headers, 1) . '</pre></details>';
+*/
+			echo "<h3>gzip encoded</h3>";
+			$response = $HTTP->doRequest('HEAD', $uri . $file . '.gz');
+			echo '<details><summary>Status: ' . $response->status . '</summary><pre>' . \print_r($response->headers, 1) . '</pre></details>';
+			$size = \filesize(APP_VERSION_ROOT_PATH.$file . '.gz');
+			if ($size == intval($response->getHeader('content-length'))) {
+				echo 'content-length matches size ' . $size;
+			} else {
+				echo 'content-length mismatch, should be ' . $size;
+			}
+
+			echo "<h3>brotli encoded</h3>";
+			$response = $HTTP->doRequest('HEAD', $uri . $file . '.br');
+			echo '<details><summary>Status: ' . $response->status . '</summary><pre>' . \print_r($response->headers, 1) . '</pre></details>';
+			$size = \filesize(APP_VERSION_ROOT_PATH.$file . '.br');
+			if ($size == intval($response->getHeader('content-length'))) {
+				echo 'content-length matches size ' . $size;
+			} else {
+				echo 'content-length mismatch, should be ' . $size;
+			}
+		}
+	}
+
+	public static function phpVersion()
+	{
+		if (PHP_VERSION_ID < 70400) {
+			return 'Your PHP version ('.PHP_VERSION.') is lower than the minimal required 7.4.0!';
+		}
+	}
+
+	public static function phpExtensions()
+	{
+		$aRequirements = array(
+			'mbstring' => extension_loaded('mbstring'),
+			'Zlib'     => extension_loaded('zlib'),
+			// enabled by default:
+			'ctype'    => extension_loaded('ctype'),
+			'json'     => function_exists('json_decode'),
+			'libxml'   => function_exists('libxml_use_internal_errors'),
+			'dom'      => class_exists('DOMDocument')
+			// https://github.com/the-djmaze/snappymail/issues/392
+		//	'phar'     => class_exists('PharData')
+		);
+
+		$aMissing = [];
+		if (in_array(false, $aRequirements)) {
+			foreach ($aRequirements as $sKey => $bValue) {
+				if (!$bValue) {
+					$aMissing[] = $sKey;
+				}
+			}
+		}
+		return $aMissing;
+	}
+
+}
diff --git a/snappymail/v/0.0.0/setup.php b/snappymail/v/0.0.0/setup.php
index c219f6cf3..870436d39 100644
--- a/snappymail/v/0.0.0/setup.php
+++ b/snappymail/v/0.0.0/setup.php
@@ -1,56 +1,17 @@
 <?php
 
-if (PHP_VERSION_ID < 70400) {
-	echo '<p style="color: red">';
-	echo '[301] Your PHP version ('.PHP_VERSION.') is lower than the minimal required 7.4.0!';
-	echo '</p>';
+require_once __DIR__ . 'app/libraries/snappymail/integrity.php';
+
+$result = \SnappyMail\Integrity::phpVersion();
+if ($result) {
+	echo '<p style="color: red">[301] ' . $result . '</p>';
 	exit(301);
 }
 
-$aOptional = array(
-	'cURL'    => extension_loaded('curl'),
-	'exif'    => extension_loaded('exif'),
-	'finfo'   => class_exists('finfo'),
-	'gd'      => extension_loaded('gd'),
-	'gnupg'   => extension_loaded('gnupg'),
-	'gmagick' => extension_loaded('gmagick'),
-	'imagick' => extension_loaded('imagick'),
-	'iconv'   => function_exists('iconv'),
-	'intl'    => function_exists('idn_to_ascii'),
-	'ldap'    => extension_loaded('ldap'),
-	'OpenSSL' => extension_loaded('openssl'),
-	'mysql'   => extension_loaded('pdo_mysql'),
-	'pgsql'   => extension_loaded('pdo_pgsql'),
-	'redis'   => extension_loaded('redis'),
-	'Sodium'  => extension_loaded('sodium'),
-	'sqlite'  => extension_loaded('pdo_sqlite'),
-	'tidy'    => extension_loaded('tidy'),
-	'uuid'    => extension_loaded('uuid'),
-	'xxtea'   => extension_loaded('xxtea'),
-	'zip'     => extension_loaded('zip')
-);
-
-$aRequirements = array(
-	'mbstring' => extension_loaded('mbstring'),
-	'Zlib'     => extension_loaded('zlib'),
-	// enabled by default:
-	'ctype'    => extension_loaded('ctype'),
-	'json'     => function_exists('json_decode'),
-	'libxml'   => function_exists('libxml_use_internal_errors'),
-	'dom'      => class_exists('DOMDocument')
-	// https://github.com/the-djmaze/snappymail/issues/392
-//	'phar'     => class_exists('PharData')
-);
-
-if (in_array(false, $aRequirements)) {
+$result = \SnappyMail\Integrity::phpExtensions();
+if ($result) {
 	echo '<p>[302] The following PHP extensions are not available in your PHP configuration!</p>';
-	echo '<ul>';
-	foreach ($aRequirements as $sKey => $bValue) {
-		if (!$bValue) {
-			echo '<li>'.$sKey.'</li>';
-		}
-	}
-	echo '</ul>';
+	echo '<ul><li>' . \implode('</li>li><li>', $result) . '</li></ul>';
 	exit(302);
 }