diff --git a/api/html/index.php b/api/html/index.php
index 300a3bd..c9e6a2f 100644
--- a/api/html/index.php
+++ b/api/html/index.php
@@ -5,6 +5,9 @@ $dotenv = Dotenv\Dotenv::createImmutable(dirname(__DIR__));
 $dotenv->load();
 
 use DI\Container;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Log\LoggerInterface;
+use Slim\Exception\HttpException;
 use Slim\Factory\AppFactory;
 use Slim\Routing\RouteCollectorProxy;
 use TorstenHettstedt\TimekeepingApi\Controller\WorkingHoursController;
@@ -50,6 +53,40 @@ $app->group('/working-hours', function (RouteCollectorProxy $group) {
     });
 });
 
-$app->addErrorMiddleware(true, true, true);
+
+// Define Custom Error Handler
+$customErrorHandler = function (
+    ServerRequestInterface $request,
+    Throwable $exception,
+    bool $displayErrorDetails,
+    bool $logErrors,
+    bool $logErrorDetails,
+    ?LoggerInterface $logger = null
+) use ($app) {
+    if ($logger !== null && $logErrors === true) {
+        $logger->error($exception->getMessage());
+    }
+    $payload = [
+        'timestamp' => date('Y-m-d\TH:m:sP'),
+        'status'    => $exception->getCode(),
+        "error"     => '',
+        'message'   => $exception->getMessage(),
+        'path'      => $exception->getFile()
+    ];
+
+    if ($exception instanceof HttpException) {
+        $payload['error'] = $exception->getTitle();
+    }
+
+    $response = $app->getResponseFactory()->createResponse($exception->getCode());
+    $response->getBody()->write(
+        json_encode($payload, JSON_UNESCAPED_UNICODE)
+    );
+
+    return $response;
+};
+
+$errorMiddleware = $app->addErrorMiddleware(true, true, true);
+$errorMiddleware->setDefaultErrorHandler($customErrorHandler);
 
 $app->run();
\ No newline at end of file