diff --git a/config/app.php b/config/app.php
index ff3bed30..3cd08e40 100644
--- a/config/app.php
+++ b/config/app.php
@@ -28,7 +28,6 @@ return [
         \Engelsystem\Renderer\TwigServiceProvider::class,
         \Engelsystem\Middleware\RouteDispatcherServiceProvider::class,
         \Engelsystem\Middleware\RequestHandlerServiceProvider::class,
-        \Engelsystem\Middleware\SessionHandlerServiceProvider::class,
         \Engelsystem\Http\Validation\ValidationServiceProvider::class,
         \Engelsystem\Http\RedirectServiceProvider::class,
 
@@ -54,6 +53,7 @@ return [
 
         // The application code
         \Engelsystem\Middleware\ErrorHandler::class,
+        \Engelsystem\Middleware\ApiRouteHandler::class,
         \Engelsystem\Middleware\VerifyCsrfToken::class,
         \Engelsystem\Middleware\RouteDispatcher::class,
         \Engelsystem\Middleware\SessionHandler::class,
diff --git a/resources/api/openapi.yml b/resources/api/openapi.yml
index 2da287f3..a67bb771 100644
--- a/resources/api/openapi.yml
+++ b/resources/api/openapi.yml
@@ -32,12 +32,31 @@ components:
       bearerFormat: API key from settings
 
   responses:
-    UnauthorizedError:
+    UnauthorizedError: # 401
       description: Access token is missing or invalid
-    ForbiddenError:
-      description: The client is not allowed to acces
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+    ForbiddenError: # 403
+      description: The client is not allowed to access
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+    NotImplementedError: # 501
+      description: This endpoint or method is not implemented
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
 
   schemas:
+    Error:
+      type: object
+      properties:
+        message:
+          type: string
     News:
       type: object
       properties:
diff --git a/src/Helpers/Authenticator.php b/src/Helpers/Authenticator.php
index 7fde7d4a..b5459dcc 100644
--- a/src/Helpers/Authenticator.php
+++ b/src/Helpers/Authenticator.php
@@ -42,7 +42,7 @@ class Authenticator
         }
 
         $this->user = $this->userFromSession();
-        if (!$this->user && request()->getAttribute('route-api', false)) {
+        if (!$this->user && request()->getAttribute('route-api-accessible', false)) {
             $this->user = $this->userFromApi();
         }
 
diff --git a/src/Middleware/ApiRouteHandler.php b/src/Middleware/ApiRouteHandler.php
new file mode 100644
index 00000000..5fe4f549
--- /dev/null
+++ b/src/Middleware/ApiRouteHandler.php
@@ -0,0 +1,93 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Engelsystem\Middleware;
+
+use Engelsystem\Exceptions\Handler;
+use Engelsystem\Http\Exceptions\HttpException;
+use Engelsystem\Http\Request;
+use Engelsystem\Http\Response;
+use Illuminate\Database\Eloquent\ModelNotFoundException;
+use Illuminate\Support\Str;
+use Nyholm\Psr7\Stream;
+use Nyholm\Psr7\Uri;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Throwable;
+
+class ApiRouteHandler implements MiddlewareInterface
+{
+    public function __construct(
+        protected ?string $apiPrefix = '/api',
+        protected ?array $apiAccessiblePaths = [
+            '/atom',
+            '/rss',
+            '/health',
+            '/ical',
+            '/metrics',
+            '/shifts-json-export',
+            '/stats',
+        ]
+    ) {
+    }
+
+    /**
+     * Process the incoming request and handling API responses
+     */
+    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
+    {
+        $path = (new Uri((string) $request->getUri()))->getPath();
+        if ($request instanceof Request) {
+            $path = $request->getPathInfo();
+        }
+
+        $path = urldecode($path);
+        $isApi = $this->apiPrefix && (Str::startsWith($path, $this->apiPrefix . '/') || $path == $this->apiPrefix);
+        $isApiAccessible = $isApi || $this->apiAccessiblePaths && in_array($path, $this->apiAccessiblePaths);
+        $request = $request
+            ->withAttribute('route-api', $isApi)
+            ->withAttribute('route-api-accessible', $isApiAccessible);
+
+        return $isApi ? $this->processApi($request, $handler) : $handler->handle($request);
+    }
+
+    /**
+     * Process the API request by ensuring that JSON is returned
+     */
+    protected function processApi(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
+    {
+        try {
+            $response = $handler->handle($request);
+        } catch (ModelNotFoundException $e) {
+            $response = new Response('', 404);
+            $response->setContent($response->getReasonPhrase());
+        } catch (HttpException $e) {
+            $response = new Response($e->getMessage(), $e->getStatusCode(), $e->getHeaders());
+            $response->setContent($response->getContent() ?: $response->getReasonPhrase());
+        } catch (Throwable $e) {
+            /** @var Handler $handler */
+            $handler = app('error.handler');
+            $handler->exceptionHandler($e, true);
+            $response = new Response('', 500);
+            $response->setContent($response->getReasonPhrase());
+        }
+
+        if (!Str::isJson((string) $response->getBody())) {
+            $content = (string) $response->getBody();
+            $content = Stream::create(json_encode([
+                'message' => $content,
+            ]));
+            $response = $response
+                ->withHeader('content-type', 'application/json')
+                ->withBody($content);
+        }
+
+        $eTag = md5((string) $response->getBody());
+        $response->setEtag($eTag);
+
+        return $response;
+    }
+}
diff --git a/src/Middleware/RouteDispatcher.php b/src/Middleware/RouteDispatcher.php
index 99568385..dcc5d05c 100644
--- a/src/Middleware/RouteDispatcher.php
+++ b/src/Middleware/RouteDispatcher.php
@@ -14,18 +14,15 @@ use Psr\Http\Server\RequestHandlerInterface;
 
 class RouteDispatcher implements MiddlewareInterface
 {
-    protected ?MiddlewareInterface $notFound = null;
-
     /**
-     * @param ResponseInterface        $response Default response
+     * @param ResponseInterface $response Default response
      * @param MiddlewareInterface|null $notFound Handles any requests if the route can't be found
      */
     public function __construct(
         protected FastRouteDispatcher $dispatcher,
         protected ResponseInterface $response,
-        MiddlewareInterface $notFound = null
+        protected ?MiddlewareInterface $notFound = null
     ) {
-        $this->notFound = $notFound;
     }
 
     /**
diff --git a/src/Middleware/SessionHandler.php b/src/Middleware/SessionHandler.php
index bf75c0e2..56274b25 100644
--- a/src/Middleware/SessionHandler.php
+++ b/src/Middleware/SessionHandler.php
@@ -4,7 +4,6 @@ declare(strict_types=1);
 
 namespace Engelsystem\Middleware;
 
-use Illuminate\Support\Str;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
 use Psr\Http\Server\MiddlewareInterface;
@@ -14,26 +13,21 @@ use Symfony\Component\HttpFoundation\Session\Storage\SessionStorageInterface;
 
 class SessionHandler implements MiddlewareInterface
 {
-    public function __construct(
-        protected SessionStorageInterface $session,
-        protected array $paths = [],
-        protected ?string $apiPrefix = null
-    ) {
+    public function __construct(protected SessionStorageInterface $session)
+    {
     }
 
     public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
     {
-        $requestPath = $request->getAttribute('route-request-path');
-        $isApi = in_array($requestPath, $this->paths)
-            || ($this->apiPrefix && Str::startsWith($requestPath, $this->apiPrefix));
-        $request = $request->withAttribute('route-api', $isApi);
-
         $return = $handler->handle($request);
 
         $cookies = $request->getCookieParams();
         if (
-            $isApi
+            // Is api (accessible) path
+            $request->getAttribute('route-api-accessible')
+            // Uses native PHP session
             && $this->session instanceof NativeSessionStorage
+            // No session cookie was sent on request
             && !isset($cookies[$this->session->getName()])
         ) {
             $this->destroyNative();
diff --git a/src/Middleware/SessionHandlerServiceProvider.php b/src/Middleware/SessionHandlerServiceProvider.php
deleted file mode 100644
index 808fdc4c..00000000
--- a/src/Middleware/SessionHandlerServiceProvider.php
+++ /dev/null
@@ -1,32 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Engelsystem\Middleware;
-
-use Engelsystem\Container\ServiceProvider;
-
-class SessionHandlerServiceProvider extends ServiceProvider
-{
-    public function register(): void
-    {
-        $this->app
-            ->when(SessionHandler::class)
-            ->needs('$paths')
-            ->give(function () {
-                return [
-                    '/atom',
-                    '/rss',
-                    '/health',
-                    '/ical',
-                    '/metrics',
-                    '/shifts-json-export',
-                    '/stats',
-                ];
-            });
-        $this->app
-            ->when(SessionHandler::class)
-            ->needs('$apiPrefix')
-            ->give('/api');
-    }
-}
diff --git a/tests/Unit/Controllers/ApiControllerTest.php b/tests/Unit/Controllers/ApiControllerTest.php
index 72430bb1..4818bfe3 100644
--- a/tests/Unit/Controllers/ApiControllerTest.php
+++ b/tests/Unit/Controllers/ApiControllerTest.php
@@ -9,7 +9,7 @@ use Engelsystem\Http\Response;
 use Engelsystem\Models\News;
 use League\OpenAPIValidation\PSR7\OperationAddress as OpenApiAddress;
 use League\OpenAPIValidation\PSR7\ResponseValidator as OpenApiResponseValidator;
-use League\OpenAPIValidation\PSR7\ValidatorBuilder;
+use League\OpenAPIValidation\PSR7\ValidatorBuilder as OpenApiValidatorBuilder;
 
 class ApiControllerTest extends ControllerTest
 {
@@ -106,7 +106,7 @@ class ApiControllerTest extends ControllerTest
         parent::setUp();
 
         $openApiDefinition = $this->app->get('path.resources.api') . '/openapi.yml';
-        $this->validator = (new ValidatorBuilder())
+        $this->validator = (new OpenApiValidatorBuilder())
             ->fromYamlFile($openApiDefinition)
             ->getResponseValidator();
     }
diff --git a/tests/Unit/Helpers/AuthenticatorTest.php b/tests/Unit/Helpers/AuthenticatorTest.php
index 973e12f5..0369ebc0 100644
--- a/tests/Unit/Helpers/AuthenticatorTest.php
+++ b/tests/Unit/Helpers/AuthenticatorTest.php
@@ -90,7 +90,7 @@ class AuthenticatorTest extends ServiceProviderTest
         $session = new Session(new MockArraySessionStorage());
 
         $request = $request->withHeader('Authorization', 'Bearer F00Bar');
-        $request = $request->withAttribute('route-api', true);
+        $request = $request->withAttribute('route-api-accessible', true);
         $this->app->instance('request', $request);
         User::factory()->create(['api_key' => 'F00Bar']);
 
@@ -160,7 +160,7 @@ class AuthenticatorTest extends ServiceProviderTest
         $this->initDatabase();
 
         $request = new Request();
-        $request = $request->withAttribute('route-api', true);
+        $request = $request->withAttribute('route-api-accessible', true);
         $session = new Session(new MockArraySessionStorage());
         $this->app->instance('request', $request);
 
diff --git a/tests/Unit/Middleware/ApiRouteHandlerTest.php b/tests/Unit/Middleware/ApiRouteHandlerTest.php
new file mode 100644
index 00000000..5cb35718
--- /dev/null
+++ b/tests/Unit/Middleware/ApiRouteHandlerTest.php
@@ -0,0 +1,172 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Engelsystem\Test\Unit\Middleware;
+
+use Engelsystem\Exceptions\Handler;
+use Engelsystem\Http\Exceptions\HttpNotFound;
+use Engelsystem\Http\Request;
+use Engelsystem\Http\Response;
+use Engelsystem\Middleware\ApiRouteHandler;
+use Engelsystem\Models\User\User;
+use Engelsystem\Test\Unit\TestCase;
+use Exception;
+use Illuminate\Database\Eloquent\ModelNotFoundException;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+
+class ApiRouteHandlerTest extends TestCase
+{
+    public function provideIsApi(): array
+    {
+        return [
+            ['/foo', false],
+            ['/lorem/api', false],
+            ['/apiDocs', false],
+            ['/api', true],
+            ['/api/', true],
+            ['/api/lorem', true],
+            ['/api/v1/testing', true],
+        ];
+    }
+
+    public function provideIsApiAccessiblePath(): array
+    {
+        return [
+            ...$this->provideIsApi(),
+            ['/metrics', true, false],
+            ['/metrics/test', false, false],
+            ['/health', true, false],
+        ];
+    }
+
+    /**
+     * @covers       \Engelsystem\Middleware\ApiRouteHandler::process
+     * @covers       \Engelsystem\Middleware\ApiRouteHandler::processApi
+     * @covers       \Engelsystem\Middleware\ApiRouteHandler::__construct
+     * @dataProvider provideIsApi
+     */
+    public function testProcessIsApi(string $uri, bool $isApi): void
+    {
+        $request = Request::create($uri);
+        /** @var RequestHandlerInterface|MockObject $handler */
+        $handler = $this->getMockForAbstractClass(RequestHandlerInterface::class);
+        $response = new Response('response content');
+
+        $handler->expects($this->once())
+            ->method('handle')
+            ->willReturnCallback(function (ServerRequestInterface $request) use ($response, $isApi) {
+                $this->assertEquals($isApi, $request->getAttribute('route-api'));
+                return $response;
+            });
+
+        $middleware = new ApiRouteHandler();
+        $apiResponse = $middleware->process($request, $handler);
+
+        if ($isApi) {
+            $this->assertEquals('application/json', $apiResponse->getHeaderLine('content-type'));
+            $this->assertEquals('{"message":"response content"}', (string) $apiResponse->getBody());
+            $this->assertNotEmpty($apiResponse->getHeaderLine('Etag'));
+        } else {
+            $this->assertEquals($response, $apiResponse);
+        }
+    }
+
+    /**
+     * @covers       \Engelsystem\Middleware\ApiRouteHandler::process
+     * @dataProvider provideIsApiAccessiblePath
+     */
+    public function testProcessIsApiAccessiblePath(string $uri, bool $isApiAccessible, bool $isOnlyApi = true): void
+    {
+        $request = Request::create($uri);
+        /** @var RequestHandlerInterface|MockObject $handler */
+        $handler = $this->getMockForAbstractClass(RequestHandlerInterface::class);
+        $response = new Response('response content');
+
+        $handler->expects($this->once())
+            ->method('handle')
+            ->willReturnCallback(function (ServerRequestInterface $request) use ($response, $isApiAccessible) {
+                $this->assertEquals($isApiAccessible, $request->getAttribute('route-api-accessible'));
+                return $response;
+            });
+
+        $middleware = new ApiRouteHandler();
+        $apiResponse = $middleware->process($request, $handler);
+
+        if (!$isOnlyApi) {
+            $this->assertEquals($response, $apiResponse);
+        }
+    }
+
+    /**
+     * @covers \Engelsystem\Middleware\ApiRouteHandler::processApi
+     */
+    public function testProcessApiModelNotFoundException(): void
+    {
+        $request = Request::create('/api/test');
+        /** @var RequestHandlerInterface|MockObject $handler */
+        $handler = $this->getMockForAbstractClass(RequestHandlerInterface::class);
+
+        $handler->expects($this->once())
+            ->method('handle')
+            ->willReturnCallback(function (): void {
+                throw new ModelNotFoundException(User::class);
+            });
+
+        $middleware = new ApiRouteHandler();
+        $response = $middleware->process($request, $handler);
+
+        $this->assertEquals(404, $response->getStatusCode());
+        $this->assertEquals('{"message":"Not Found"}', (string) $response->getBody());
+    }
+
+    /**
+     * @covers \Engelsystem\Middleware\ApiRouteHandler::processApi
+     */
+    public function testProcessApiHttpException(): void
+    {
+        $request = Request::create('/api/test');
+        /** @var RequestHandlerInterface|MockObject $handler */
+        $handler = $this->getMockForAbstractClass(RequestHandlerInterface::class);
+
+        $handler->expects($this->once())
+            ->method('handle')
+            ->willReturnCallback(function (): void {
+                throw new HttpNotFound();
+            });
+
+        $middleware = new ApiRouteHandler();
+        $response = $middleware->process($request, $handler);
+
+        $this->assertEquals(404, $response->getStatusCode());
+        $this->assertEquals('{"message":"Not Found"}', (string) $response->getBody());
+    }
+
+    /**
+     * @covers \Engelsystem\Middleware\ApiRouteHandler::processApi
+     */
+    public function testProcessGenericException(): void
+    {
+        $e = new Exception();
+        $request = Request::create('/api/test');
+        /** @var RequestHandlerInterface|MockObject $handler */
+        $handler = $this->getMockForAbstractClass(RequestHandlerInterface::class);
+        $errorHandler = $this->createMock(Handler::class);
+        $this->setExpects($errorHandler, 'exceptionHandler', [$e, true], '', $this->once());
+        $this->app->instance('error.handler', $errorHandler);
+
+        $handler->expects($this->once())
+            ->method('handle')
+            ->willReturnCallback(function () use ($e): void {
+                throw $e;
+            });
+
+        $middleware = new ApiRouteHandler();
+        $response = $middleware->process($request, $handler);
+
+        $this->assertEquals(500, $response->getStatusCode());
+        $this->assertEquals('{"message":"Internal Server Error"}', (string) $response->getBody());
+    }
+}
diff --git a/tests/Unit/Middleware/SessionHandlerServiceProviderTest.php b/tests/Unit/Middleware/SessionHandlerServiceProviderTest.php
deleted file mode 100644
index 61e1ed7a..00000000
--- a/tests/Unit/Middleware/SessionHandlerServiceProviderTest.php
+++ /dev/null
@@ -1,46 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Engelsystem\Test\Unit\Middleware;
-
-use Engelsystem\Middleware\SessionHandler;
-use Engelsystem\Middleware\SessionHandlerServiceProvider;
-use Engelsystem\Test\Unit\ServiceProviderTest;
-use Illuminate\Contracts\Container\ContextualBindingBuilder;
-use PHPUnit\Framework\MockObject\MockObject;
-
-class SessionHandlerServiceProviderTest extends ServiceProviderTest
-{
-    /**
-     * @covers \Engelsystem\Middleware\SessionHandlerServiceProvider::register()
-     */
-    public function testRegister(): void
-    {
-        /** @var ContextualBindingBuilder|MockObject $bindingBuilder */
-        $bindingBuilder = $this->createMock(ContextualBindingBuilder::class);
-        $app = $this->getApp(['when']);
-
-        $app->expects($this->once())
-            ->method('when')
-            ->with(SessionHandler::class)
-            ->willReturn($bindingBuilder);
-
-        $bindingBuilder->expects($this->once())
-            ->method('needs')
-            ->with('$paths')
-            ->willReturn($bindingBuilder);
-
-        $bindingBuilder->expects($this->once())
-            ->method('give')
-            ->willReturnCallback(function (callable $callable): void {
-                $paths = $callable();
-
-                $this->assertIsArray($paths);
-                $this->assertTrue(in_array('/metrics', $paths));
-            });
-
-        $serviceProvider = new SessionHandlerServiceProvider($app);
-        $serviceProvider->register();
-    }
-}
diff --git a/tests/Unit/Middleware/SessionHandlerTest.php b/tests/Unit/Middleware/SessionHandlerTest.php
index 51b3ea52..d24168fc 100644
--- a/tests/Unit/Middleware/SessionHandlerTest.php
+++ b/tests/Unit/Middleware/SessionHandlerTest.php
@@ -40,13 +40,8 @@ class SessionHandlerTest extends TestCase
 
         $request->expects($this->exactly(2))
             ->method('getAttribute')
-            ->with('route-request-path')
-            ->willReturnOnConsecutiveCalls('/foo', '/lorem');
-
-        $request->expects($this->exactly(2))
-            ->method('withAttribute')
-            ->withConsecutive(['route-api', true], ['route-api', false])
-            ->willReturn($request);
+            ->with('route-api-accessible')
+            ->willReturnOnConsecutiveCalls(true, false);
 
         $sessionStorage->expects($this->once())
             ->method('getName')