diff --git a/src/FallbackHandler.php b/src/FallbackHandler.php
new file mode 100644
index 0000000..9769361
--- /dev/null
+++ b/src/FallbackHandler.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace K9u\Framework;
+
+use Psr\Http\Message\ResponseFactoryInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+
+class FallbackHandler implements RequestHandlerInterface
+{
+    private ResponseFactoryInterface $responseFactory;
+
+    public function __construct(ResponseFactoryInterface $responseFactory)
+    {
+        $this->responseFactory = $responseFactory;
+    }
+
+    public function handle(ServerRequestInterface $request): ResponseInterface
+    {
+        unset($request); // unused
+
+        return $this->responseFactory->createResponse(503);
+    }
+}
diff --git a/src/FrameworkModule.php b/src/FrameworkModule.php
index 7cb557c..884d2f1 100644
--- a/src/FrameworkModule.php
+++ b/src/FrameworkModule.php
@@ -24,9 +24,9 @@ class FrameworkModule extends AbstractModule
      * @param array<class-string> $middlewares
      * @param AbstractModule|null $module
      */
-    public function __construct(array $middlewares, AbstractModule $module = null)
+    public function __construct(array $middlewares = [], AbstractModule $module = null)
     {
-        $this->middlewares = $middlewares;
+        $this->middlewares = array_merge($middlewares, [FallbackHandler::class]);
         parent::__construct($module);
     }
 
diff --git a/tests/FrameworkModuleTest.php b/tests/FrameworkModuleTest.php
index 649a481..6c75dae 100644
--- a/tests/FrameworkModuleTest.php
+++ b/tests/FrameworkModuleTest.php
@@ -16,11 +16,7 @@ public function setUp(): void
 
     public function testCompile(): void
     {
-        $module = new FrameworkModule([
-            FakeMiddleware::class,
-            FakeRequestHandler::class
-        ]);
-
+        $module = new FrameworkModule();
         $compiler = new DiCompiler($module, __DIR__ . '/../build/tests');
         $instance = $compiler->getInstance(ApplicationInterface::class);