diff --git a/CODING-CHALLENGE-6.md b/CODING-CHALLENGE-6.md
new file mode 100644
index 0000000..336e40b
--- /dev/null
+++ b/CODING-CHALLENGE-6.md
@@ -0,0 +1,16 @@
+# RESTful Webservices in Symfony
+
+## Coding Challenge 6 - POST vs. PUT
+
+### Tasks
+
+- implement controllers to create and update attendees and workshops
+- both should be possible with JSON and XML
+
+### Solution
+
+- use an `ArgumentValueResolver` (or alternativly the new `#[MapRequestPayload]` attribute) to deserialize the request's content
+- use the `*Repository`s to save the object into the database
+- *CREATE:* use HTTP method `POST`, return an HTTP 201 (Created) status code and
+  set the `Location` header with the help of the `UrlGenerator`
+- *UPDATE:* use HTTP method `PUT`, return an HTTP 204 (No Content) status code and leave the response body empty
diff --git a/CODING-CHALLENGE-7.md b/CODING-CHALLENGE-7.md
new file mode 100644
index 0000000..fe16d2d
--- /dev/null
+++ b/CODING-CHALLENGE-7.md
@@ -0,0 +1,14 @@
+# RESTful Webservices in Symfony
+
+## Coding Challenge 7 - Validation
+
+### Tasks
+
+- introduce Symfony's Validator to validate the request content used to create and update workshops and attendees
+
+### Solution
+
+- require the Symfony Validator component: `composer require validator`
+- add validation constraints to your model properties (e.g. NotBlank, Email)
+- inject the `Validator` Service in your `ValueResolver`s
+- for now throw an `UnprocessableEntityHttpException` on validation errors
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 031825a..23b8d21 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,8 @@
         "symfony/runtime": "6.3.*",
         "symfony/serializer": "6.3.*",
         "symfony/yaml": "6.3.*",
-        "webmozart/assert": "^1.11"
+        "webmozart/assert": "^1.11",
+        "willdurand/negotiation": "^3.1"
     },
     "config": {
         "allow-plugins": {
diff --git a/composer.lock b/composer.lock
index e49b66b..e5832d7 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "81fadf3eb9b9ecfbe68ef98a2e841210",
+    "content-hash": "5596bf499dc7ce184640fa9df83b1cb1",
     "packages": [
         {
             "name": "brick/math",
@@ -333,16 +333,16 @@
         },
         {
             "name": "doctrine/dbal",
-            "version": "3.6.7",
+            "version": "3.7.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/doctrine/dbal.git",
-                "reference": "8e0e268052b4a8974cb00215bb2892787021614f"
+                "reference": "00d03067f07482f025d41ab55e4ba0db5eca2cdf"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/doctrine/dbal/zipball/8e0e268052b4a8974cb00215bb2892787021614f",
-                "reference": "8e0e268052b4a8974cb00215bb2892787021614f",
+                "url": "https://api.github.com/repos/doctrine/dbal/zipball/00d03067f07482f025d41ab55e4ba0db5eca2cdf",
+                "reference": "00d03067f07482f025d41ab55e4ba0db5eca2cdf",
                 "shasum": ""
             },
             "require": {
@@ -358,9 +358,9 @@
                 "doctrine/coding-standard": "12.0.0",
                 "fig/log-test": "^1",
                 "jetbrains/phpstorm-stubs": "2023.1",
-                "phpstan/phpstan": "1.10.34",
+                "phpstan/phpstan": "1.10.35",
                 "phpstan/phpstan-strict-rules": "^1.5",
-                "phpunit/phpunit": "9.6.12",
+                "phpunit/phpunit": "9.6.13",
                 "psalm/plugin-phpunit": "0.18.4",
                 "slevomat/coding-standard": "8.13.1",
                 "squizlabs/php_codesniffer": "3.7.2",
@@ -426,7 +426,7 @@
             ],
             "support": {
                 "issues": "https://github.com/doctrine/dbal/issues",
-                "source": "https://github.com/doctrine/dbal/tree/3.6.7"
+                "source": "https://github.com/doctrine/dbal/tree/3.7.0"
             },
             "funding": [
                 {
@@ -442,20 +442,20 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2023-09-19T20:15:41+00:00"
+            "time": "2023-09-26T20:56:55+00:00"
         },
         {
             "name": "doctrine/deprecations",
-            "version": "v1.1.1",
+            "version": "1.1.2",
             "source": {
                 "type": "git",
                 "url": "https://github.com/doctrine/deprecations.git",
-                "reference": "612a3ee5ab0d5dd97b7cf3874a6efe24325efac3"
+                "reference": "4f2d4f2836e7ec4e7a8625e75c6aa916004db931"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/doctrine/deprecations/zipball/612a3ee5ab0d5dd97b7cf3874a6efe24325efac3",
-                "reference": "612a3ee5ab0d5dd97b7cf3874a6efe24325efac3",
+                "url": "https://api.github.com/repos/doctrine/deprecations/zipball/4f2d4f2836e7ec4e7a8625e75c6aa916004db931",
+                "reference": "4f2d4f2836e7ec4e7a8625e75c6aa916004db931",
                 "shasum": ""
             },
             "require": {
@@ -487,9 +487,9 @@
             "homepage": "https://www.doctrine-project.org/",
             "support": {
                 "issues": "https://github.com/doctrine/deprecations/issues",
-                "source": "https://github.com/doctrine/deprecations/tree/v1.1.1"
+                "source": "https://github.com/doctrine/deprecations/tree/1.1.2"
             },
-            "time": "2023-06-03T09:27:29+00:00"
+            "time": "2023-09-27T20:04:15+00:00"
         },
         {
             "name": "doctrine/doctrine-bundle",
@@ -4746,6 +4746,62 @@
                 "source": "https://github.com/webmozarts/assert/tree/1.11.0"
             },
             "time": "2022-06-03T18:03:27+00:00"
+        },
+        {
+            "name": "willdurand/negotiation",
+            "version": "3.1.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/willdurand/Negotiation.git",
+                "reference": "68e9ea0553ef6e2ee8db5c1d98829f111e623ec2"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/willdurand/Negotiation/zipball/68e9ea0553ef6e2ee8db5c1d98829f111e623ec2",
+                "reference": "68e9ea0553ef6e2ee8db5c1d98829f111e623ec2",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.1.0"
+            },
+            "require-dev": {
+                "symfony/phpunit-bridge": "^5.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.0-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Negotiation\\": "src/Negotiation"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "William Durand",
+                    "email": "will+git@drnd.me"
+                }
+            ],
+            "description": "Content Negotiation tools for PHP provided as a standalone library.",
+            "homepage": "http://williamdurand.fr/Negotiation/",
+            "keywords": [
+                "accept",
+                "content",
+                "format",
+                "header",
+                "negotiation"
+            ],
+            "support": {
+                "issues": "https://github.com/willdurand/Negotiation/issues",
+                "source": "https://github.com/willdurand/Negotiation/tree/3.1.0"
+            },
+            "time": "2022-01-30T20:08:53+00:00"
         }
     ],
     "packages-dev": [
@@ -5119,16 +5175,16 @@
         },
         {
             "name": "friendsofphp/php-cs-fixer",
-            "version": "v3.29.0",
+            "version": "v3.30.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/PHP-CS-Fixer/PHP-CS-Fixer.git",
-                "reference": "a55c488e8bfdd9b315880095cd02fa0e49e884d8"
+                "reference": "95c64693b2f149966a2bc05a7a4981b0343ea52f"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/PHP-CS-Fixer/PHP-CS-Fixer/zipball/a55c488e8bfdd9b315880095cd02fa0e49e884d8",
-                "reference": "a55c488e8bfdd9b315880095cd02fa0e49e884d8",
+                "url": "https://api.github.com/repos/PHP-CS-Fixer/PHP-CS-Fixer/zipball/95c64693b2f149966a2bc05a7a4981b0343ea52f",
+                "reference": "95c64693b2f149966a2bc05a7a4981b0343ea52f",
                 "shasum": ""
             },
             "require": {
@@ -5202,7 +5258,7 @@
             ],
             "support": {
                 "issues": "https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/issues",
-                "source": "https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/tree/v3.29.0"
+                "source": "https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/tree/v3.30.0"
             },
             "funding": [
                 {
@@ -5210,7 +5266,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2023-09-26T13:02:53+00:00"
+            "time": "2023-09-26T22:10:43+00:00"
         },
         {
             "name": "hautelook/alice-bundle",
@@ -6340,16 +6396,16 @@
         },
         {
             "name": "sebastian/complexity",
-            "version": "3.0.1",
+            "version": "3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/complexity.git",
-                "reference": "c70b73893e10757af9c6a48929fa6a333b56a97a"
+                "reference": "68cfb347a44871f01e33ab0ef8215966432f6957"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/complexity/zipball/c70b73893e10757af9c6a48929fa6a333b56a97a",
-                "reference": "c70b73893e10757af9c6a48929fa6a333b56a97a",
+                "url": "https://api.github.com/repos/sebastianbergmann/complexity/zipball/68cfb347a44871f01e33ab0ef8215966432f6957",
+                "reference": "68cfb347a44871f01e33ab0ef8215966432f6957",
                 "shasum": ""
             },
             "require": {
@@ -6362,7 +6418,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-main": "3.0-dev"
+                    "dev-main": "3.1-dev"
                 }
             },
             "autoload": {
@@ -6386,7 +6442,7 @@
             "support": {
                 "issues": "https://github.com/sebastianbergmann/complexity/issues",
                 "security": "https://github.com/sebastianbergmann/complexity/security/policy",
-                "source": "https://github.com/sebastianbergmann/complexity/tree/3.0.1"
+                "source": "https://github.com/sebastianbergmann/complexity/tree/3.1.0"
             },
             "funding": [
                 {
@@ -6394,7 +6450,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2023-08-31T09:55:53+00:00"
+            "time": "2023-09-28T11:50:59+00:00"
         },
         {
             "name": "sebastian/diff",
diff --git a/src/Controller/Attendee/ListController.php b/src/Controller/Attendee/ListController.php
index 9cd970b..558a1cb 100644
--- a/src/Controller/Attendee/ListController.php
+++ b/src/Controller/Attendee/ListController.php
@@ -27,10 +27,8 @@ public function __invoke(Request $request): Response
             $request->query->getInt('size', 10)
         );
 
-        $serializedAttendeeCollection = $this->serializer->serialize($attendeeCollection, 'json');
+        $serializedAttendeeCollection = $this->serializer->serialize($attendeeCollection, $request->getRequestFormat());
 
-        return new Response($serializedAttendeeCollection, Response::HTTP_OK, [
-            'Content-Type' => 'application/json',
-        ]);
+        return new Response($serializedAttendeeCollection, Response::HTTP_OK);
     }
 }
diff --git a/src/Controller/Attendee/ReadController.php b/src/Controller/Attendee/ReadController.php
index 5b12ac1..ed626de 100644
--- a/src/Controller/Attendee/ReadController.php
+++ b/src/Controller/Attendee/ReadController.php
@@ -5,6 +5,7 @@
 namespace App\Controller\Attendee;
 
 use App\Entity\Attendee;
+use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Routing\Annotation\Route;
 use Symfony\Component\Serializer\SerializerInterface;
@@ -17,12 +18,10 @@ public function __construct(
     ) {
     }
 
-    public function __invoke(Attendee $attendee): Response
+    public function __invoke(Request $request, Attendee $attendee): Response
     {
-        $serializedAttendee = $this->serializer->serialize($attendee, 'json');
+        $serializedAttendee = $this->serializer->serialize($attendee, $request->getRequestFormat());
 
-        return new Response($serializedAttendee, Response::HTTP_OK, [
-            'Content-Type' => 'application/json',
-        ]);
+        return new Response($serializedAttendee, Response::HTTP_OK);
     }
 }
diff --git a/src/Controller/Workshop/ListController.php b/src/Controller/Workshop/ListController.php
index f65ecd7..99235ff 100644
--- a/src/Controller/Workshop/ListController.php
+++ b/src/Controller/Workshop/ListController.php
@@ -27,10 +27,8 @@ public function __invoke(Request $request): Response
             $request->query->getInt('size', 10)
         );
 
-        $serializedWorkshopCollection = $this->serializer->serialize($workshopCollection, 'json');
+        $serializedWorkshopCollection = $this->serializer->serialize($workshopCollection, $request->getRequestFormat());
 
-        return new Response($serializedWorkshopCollection, Response::HTTP_OK, [
-            'Content-Type' => 'application/json',
-        ]);
+        return new Response($serializedWorkshopCollection, Response::HTTP_OK);
     }
 }
diff --git a/src/Controller/Workshop/ReadController.php b/src/Controller/Workshop/ReadController.php
index f0feec1..3bed2ee 100644
--- a/src/Controller/Workshop/ReadController.php
+++ b/src/Controller/Workshop/ReadController.php
@@ -5,6 +5,7 @@
 namespace App\Controller\Workshop;
 
 use App\Entity\Workshop;
+use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Routing\Annotation\Route;
 use Symfony\Component\Serializer\SerializerInterface;
@@ -17,12 +18,10 @@ public function __construct(
     ) {
     }
 
-    public function __invoke(Workshop $workshop): Response
+    public function __invoke(Request $request, Workshop $workshop): Response
     {
-        $serializedWorkshop = $this->serializer->serialize($workshop, 'json');
+        $serializedWorkshop = $this->serializer->serialize($workshop, $request->getRequestFormat());
 
-        return new Response($serializedWorkshop, Response::HTTP_OK, [
-            'Content-Type' => 'application/json',
-        ]);
+        return new Response($serializedWorkshop, Response::HTTP_OK);
     }
 }
diff --git a/src/EventListener/RequestFormatListener.php b/src/EventListener/RequestFormatListener.php
new file mode 100644
index 0000000..069d445
--- /dev/null
+++ b/src/EventListener/RequestFormatListener.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\EventListener;
+
+use App\Negotiation\ContentNegotiator;
+use App\Negotiation\MimeType;
+use App\Negotiation\RequestFormat;
+use Symfony\Component\EventDispatcher\Attribute\AsEventListener;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Event\RequestEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+
+#[AsEventListener(event: KernelEvents::REQUEST, method: 'onKernelRequest', priority: 8)]
+final class RequestFormatListener
+{
+    private array $formats = [
+        RequestFormat::JSON => MimeType::JSON,
+        RequestFormat::JSON_HAL => MimeType::JSON_HAL,
+        RequestFormat::XML => MimeType::XML,
+    ];
+
+    public function __construct(
+        private ContentNegotiator $contentNegotiator
+    ) {
+    }
+
+    public function onKernelRequest(RequestEvent $event): void
+    {
+        $request = $event->getRequest();
+
+        $this->addRequestFormats($request, $this->formats);
+
+        $request->setRequestFormat(
+            $this->contentNegotiator->getNegotiatedRequestFormat()
+        );
+    }
+
+    /**
+     * Adds the supported formats to the request.
+     *
+     * This is necessary for {@see Request::getMimeType} to work.
+     */
+    private function addRequestFormats(Request $request, array $formats): void
+    {
+        foreach ($formats as $format => $mimeType) {
+            $request->setFormat($format, $mimeType);
+        }
+    }
+}
diff --git a/src/EventListener/ResponseContentTypeListener.php b/src/EventListener/ResponseContentTypeListener.php
new file mode 100644
index 0000000..8c6f19d
--- /dev/null
+++ b/src/EventListener/ResponseContentTypeListener.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\EventListener;
+
+use Symfony\Component\EventDispatcher\Attribute\AsEventListener;
+use Symfony\Component\HttpKernel\Event\ResponseEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+
+#[AsEventListener(event: KernelEvents::RESPONSE, method: 'onKernelResponse', priority: 8)]
+final class ResponseContentTypeListener
+{
+    public function onKernelResponse(ResponseEvent $event): void
+    {
+        $request = $event->getRequest();
+        $response = $event->getResponse();
+
+        $response->headers->set(
+            'Content-Type',
+            sprintf('%s; charset=utf-8', $request->getMimeType($request->getRequestFormat()))
+        );
+    }
+}
diff --git a/src/Negotiation/ContentNegotiator.php b/src/Negotiation/ContentNegotiator.php
new file mode 100644
index 0000000..bca48bf
--- /dev/null
+++ b/src/Negotiation/ContentNegotiator.php
@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Negotiation;
+
+use Negotiation\Negotiator;
+use Symfony\Component\HttpFoundation\RequestStack;
+use Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException;
+
+final class ContentNegotiator
+{
+    private const SUPPORTED_MIME_TYPES = [
+        MimeType::JSON,
+        MimeType::JSON_HAL,
+        MimeType::XML,
+    ];
+
+    private Negotiator $negotiator;
+
+    public function __construct(
+        private readonly RequestStack $requestStack
+    ) {
+        $this->negotiator = new Negotiator();
+    }
+
+    public function isNegotiatedRequestFormat(string $format): bool
+    {
+        return $format === $this->getNegotiatedRequestFormat();
+    }
+
+    // this is used to set the correct serialization format
+    public function getNegotiatedRequestFormat(): string
+    {
+        $acceptableContentTypes = $this->requestStack->getCurrentRequest()->getAcceptableContentTypes();
+
+        $mimeType = $this->getNegotiatedMimeType($acceptableContentTypes);
+
+        if (!$mimeType || !in_array($mimeType, self::SUPPORTED_MIME_TYPES, true)) {
+            throw $this->getNotAcceptableHttpException($acceptableContentTypes, self::SUPPORTED_MIME_TYPES);
+        }
+
+        return match ($mimeType) {
+            MimeType::JSON_HAL => RequestFormat::JSON_HAL,
+            MimeType::XML => RequestFormat::XML,
+            default => RequestFormat::JSON,
+        };
+    }
+
+    private function getNegotiatedMimeType(array $acceptableContentTypes): ?string
+    {
+        // default is application/json
+        if (empty($acceptableContentTypes)) {
+            return MimeType::JSON;
+        }
+
+        // default is application/json
+        if (1 === count($acceptableContentTypes) && '*/*' === $acceptableContentTypes[0]) {
+            return MimeType::JSON;
+        }
+
+        $acceptableContentTypesAsString = implode(',', $acceptableContentTypes);
+
+        $acceptHeader = $this->negotiator->getBest($acceptableContentTypesAsString, self::SUPPORTED_MIME_TYPES);
+
+        return $acceptHeader?->getType();
+    }
+
+    private function getNotAcceptableHttpException(array $accepts, array $mimeTypes): NotAcceptableHttpException
+    {
+        return new NotAcceptableHttpException(sprintf(
+            'Requested format "%s" is not supported. Supported MIME types are "%s".',
+            implode('", "', $accepts),
+            implode('", "', $mimeTypes)
+        ));
+    }
+}
diff --git a/src/Negotiation/MimeType.php b/src/Negotiation/MimeType.php
new file mode 100644
index 0000000..3468b1e
--- /dev/null
+++ b/src/Negotiation/MimeType.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Negotiation;
+
+final class MimeType
+{
+    public const JSON = 'application/json';
+    public const JSON_HAL = 'application/hal+json';
+    public const XML = 'text/xml';
+}
diff --git a/src/Negotiation/RequestFormat.php b/src/Negotiation/RequestFormat.php
new file mode 100644
index 0000000..305f296
--- /dev/null
+++ b/src/Negotiation/RequestFormat.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Negotiation;
+
+final class RequestFormat
+{
+    public const JSON = 'json';
+    public const JSON_HAL = 'jsonhal';
+    public const XML = 'xml';
+}
diff --git a/src/Pagination/AttendeeCollectionFactory.php b/src/Pagination/AttendeeCollectionFactory.php
index 42738e7..8606c7b 100644
--- a/src/Pagination/AttendeeCollectionFactory.php
+++ b/src/Pagination/AttendeeCollectionFactory.php
@@ -4,6 +4,7 @@
 
 namespace App\Pagination;
 
+use App\Negotiation\ContentNegotiator;
 use App\Repository\AttendeeRepository;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepositoryInterface;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
@@ -13,8 +14,9 @@ final class AttendeeCollectionFactory extends PaginatedCollectionFactory
     public function __construct(
         private readonly AttendeeRepository $attendeeRepository,
         UrlGeneratorInterface $urlGenerator,
+        ContentNegotiator $contentNegotiator,
     ) {
-        parent::__construct($urlGenerator);
+        parent::__construct($urlGenerator, $contentNegotiator);
     }
 
     public function getRepository(): ServiceEntityRepositoryInterface
diff --git a/src/Pagination/PaginatedCollection.php b/src/Pagination/PaginatedCollection.php
index 5ff5cbc..5204d7c 100644
--- a/src/Pagination/PaginatedCollection.php
+++ b/src/Pagination/PaginatedCollection.php
@@ -13,7 +13,7 @@ final class PaginatedCollection
     public readonly int $count;
 
     #[SerializedName('_links')]
-    public array $links;
+    public ?array $links;
 
     public function __construct(\Iterator $items, int $total)
     {
diff --git a/src/Pagination/PaginatedCollectionFactory.php b/src/Pagination/PaginatedCollectionFactory.php
index 90b0490..93b3994 100644
--- a/src/Pagination/PaginatedCollectionFactory.php
+++ b/src/Pagination/PaginatedCollectionFactory.php
@@ -4,6 +4,8 @@
 
 namespace App\Pagination;
 
+use App\Negotiation\ContentNegotiator;
+use App\Negotiation\RequestFormat;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepositoryInterface;
 use Doctrine\ORM\Tools\Pagination\Paginator;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
@@ -11,7 +13,8 @@
 abstract class PaginatedCollectionFactory
 {
     public function __construct(
-        private readonly UrlGeneratorInterface $urlGenerator
+        private readonly UrlGeneratorInterface $urlGenerator,
+        private readonly ContentNegotiator $contentNegotiator,
     ) {
     }
 
@@ -39,6 +42,10 @@ public function create(int $page, int $size): PaginatedCollection
 
         $paginatedCollection = new PaginatedCollection($paginator->getIterator(), $total);
 
+        if (!$this->contentNegotiator->isNegotiatedRequestFormat(RequestFormat::JSON_HAL)) {
+            return $paginatedCollection;
+        }
+
         $routeName = $this->getRouteName();
 
         $paginatedCollection
diff --git a/src/Pagination/WorkshopCollectionFactory.php b/src/Pagination/WorkshopCollectionFactory.php
index d22442c..9301974 100644
--- a/src/Pagination/WorkshopCollectionFactory.php
+++ b/src/Pagination/WorkshopCollectionFactory.php
@@ -4,6 +4,7 @@
 
 namespace App\Pagination;
 
+use App\Negotiation\ContentNegotiator;
 use App\Repository\WorkshopRepository;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepositoryInterface;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
@@ -13,8 +14,9 @@ final class WorkshopCollectionFactory extends PaginatedCollectionFactory
     public function __construct(
         private readonly WorkshopRepository $workshopRepository,
         UrlGeneratorInterface $urlGenerator,
+        ContentNegotiator $contentNegotiator,
     ) {
-        parent::__construct($urlGenerator);
+        parent::__construct($urlGenerator, $contentNegotiator);
     }
 
     public function getRepository(): ServiceEntityRepositoryInterface
diff --git a/src/Serializer/AttendeeNormalizer.php b/src/Serializer/AttendeeNormalizer.php
index 29081a0..fe8117d 100644
--- a/src/Serializer/AttendeeNormalizer.php
+++ b/src/Serializer/AttendeeNormalizer.php
@@ -5,6 +5,7 @@
 namespace App\Serializer;
 
 use App\Entity\Attendee;
+use App\Negotiation\RequestFormat;
 use Symfony\Component\DependencyInjection\Attribute\Autowire;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Symfony\Component\Serializer\Normalizer\AbstractNormalizer;
@@ -41,14 +42,20 @@ public function normalize($object, string $format = null, array $context = [])
 
         $data = $this->normalizer->normalize($object, $format, $context);
 
-        if (\is_array($data)) {
-            $data['_links']['self']['href'] = $this->urlGenerator->generate('read_workshop', [
-                'identifier' => $object->getIdentifier(),
-            ]);
+        if (!\is_array($data)) {
+            return $data;
+        }
 
-            $data['_links']['collection']['href'] = $this->urlGenerator->generate('list_workshop');
+        if (RequestFormat::JSON_HAL !== $format) {
+            return $data;
         }
 
+        $data['_links']['self']['href'] = $this->urlGenerator->generate('read_workshop', [
+            'identifier' => $object->getIdentifier(),
+        ]);
+
+        $data['_links']['collection']['href'] = $this->urlGenerator->generate('list_workshop');
+
         return $data;
     }
 
diff --git a/src/Serializer/Encoder/JsonHalEncoder.php b/src/Serializer/Encoder/JsonHalEncoder.php
new file mode 100644
index 0000000..0293ed2
--- /dev/null
+++ b/src/Serializer/Encoder/JsonHalEncoder.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Serializer\Encoder;
+
+use Symfony\Component\Serializer\Encoder\JsonEncoder;
+
+final class JsonHalEncoder extends JsonEncoder
+{
+    public const FORMAT = 'jsonhal';
+
+    public function supportsEncoding(string $format): bool
+    {
+        return self::FORMAT === $format;
+    }
+}
diff --git a/src/Serializer/WorkshopNormalizer.php b/src/Serializer/WorkshopNormalizer.php
index e0fdf0b..997574a 100644
--- a/src/Serializer/WorkshopNormalizer.php
+++ b/src/Serializer/WorkshopNormalizer.php
@@ -5,6 +5,7 @@
 namespace App\Serializer;
 
 use App\Entity\Workshop;
+use App\Negotiation\RequestFormat;
 use Symfony\Component\DependencyInjection\Attribute\Autowire;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Symfony\Component\Serializer\Normalizer\AbstractNormalizer;
@@ -41,14 +42,20 @@ public function normalize($object, string $format = null, array $context = [])
 
         $data = $this->normalizer->normalize($object, $format, $context);
 
-        if (\is_array($data)) {
-            $data['_links']['self']['href'] = $this->urlGenerator->generate('read_attendee', [
-                'identifier' => $object->getIdentifier(),
-            ]);
+        if (!\is_array($data)) {
+            return $data;
+        }
 
-            $data['_links']['collection']['href'] = $this->urlGenerator->generate('list_attendee');
+        if (RequestFormat::JSON_HAL !== $format) {
+            return $data;
         }
 
+        $data['_links']['self']['href'] = $this->urlGenerator->generate('read_attendee', [
+            'identifier' => $object->getIdentifier(),
+        ]);
+
+        $data['_links']['collection']['href'] = $this->urlGenerator->generate('list_attendee');
+
         return $data;
     }
 
diff --git a/tests/Controller/Attendee/ListControllerTest.php b/tests/Controller/Attendee/ListControllerTest.php
index 5e590ac..fb53c32 100644
--- a/tests/Controller/Attendee/ListControllerTest.php
+++ b/tests/Controller/Attendee/ListControllerTest.php
@@ -8,15 +8,27 @@
 
 class ListControllerTest extends ApiTestCase
 {
-    public function test_it_should_list_all_attendees(): void
+    public static function provideHttpAcceptHeaderValues(): \Generator
+    {
+        yield 'json' => ['application/json'];
+        yield 'hal+json' => ['application/hal+json'];
+    }
+
+    /**
+     * @dataProvider provideHttpAcceptHeaderValues
+     */
+    public function test_it_should_list_all_attendees(string $httpAcceptHeaderValue): void
     {
         $this->loadFixtures([
             __DIR__.'/fixtures/list_attendee.yaml',
         ]);
 
-        $this->browser->request('GET', '/attendees');
+        $this->browser->request('GET', '/attendees', [], [], [
+            'HTTP_ACCEPT' => $httpAcceptHeaderValue,
+        ]);
 
         static::assertResponseIsSuccessful();
+        static::assertStringContainsString($httpAcceptHeaderValue, $this->browser->getResponse()->headers->get('Content-Type'));
 
         $this->assertMatchesJsonSnapshot($this->browser->getResponse()->getContent());
     }
diff --git a/tests/Controller/Attendee/ReadControllerTest.php b/tests/Controller/Attendee/ReadControllerTest.php
index 3ac2e18..c00142c 100644
--- a/tests/Controller/Attendee/ReadControllerTest.php
+++ b/tests/Controller/Attendee/ReadControllerTest.php
@@ -8,15 +8,27 @@
 
 class ReadControllerTest extends ApiTestCase
 {
-    public function test_it_should_show_requested_attendee(): void
+    public static function provideHttpAcceptHeaderValues(): \Generator
+    {
+        yield 'json' => ['application/json'];
+        yield 'hal+json' => ['application/hal+json'];
+    }
+
+    /**
+     * @dataProvider provideHttpAcceptHeaderValues
+     */
+    public function test_it_should_show_requested_attendee(string $httpAcceptHeaderValue): void
     {
         $this->loadFixtures([
             __DIR__.'/fixtures/read_attendee.yaml',
         ]);
 
-        $this->browser->request('GET', '/attendees/17058af8-1b0f-4afe-910d-669b4bd0fd26');
+        $this->browser->request('GET', '/attendees/17058af8-1b0f-4afe-910d-669b4bd0fd26', [], [], [
+            'HTTP_ACCEPT' => $httpAcceptHeaderValue,
+        ]);
 
         static::assertResponseIsSuccessful();
+        static::assertStringContainsString($httpAcceptHeaderValue, $this->browser->getResponse()->headers->get('Content-Type'));
 
         $this->assertMatchesJsonSnapshot($this->browser->getResponse()->getContent());
     }
diff --git a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_list_all_attendees with data set haljson__1.json b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_list_all_attendees with data set haljson__1.json
new file mode 100644
index 0000000..543aa13
--- /dev/null
+++ b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_list_all_attendees with data set haljson__1.json	
@@ -0,0 +1,43 @@
+{
+    "items": [
+        {
+            "identifier": "803449f4-9a4c-4ecb-8ce4-cebc804fe70a",
+            "firstname": "Jan",
+            "lastname": "Sch\u00e4dlich",
+            "email": "schaedlich.jan@gmail.com",
+            "workshops": [
+                {
+                    "identifier": "abba667a-96ae-4f75-9b71-97819b682e8d",
+                    "title": "RESTful Webservices in Symfony",
+                    "workshop_date": "2022-06-14",
+                    "attendees": [
+                        "Jan Sch\u00e4dlich"
+                    ],
+                    "_links": {
+                        "self": {
+                            "href": "\/attendees\/abba667a-96ae-4f75-9b71-97819b682e8d"
+                        },
+                        "collection": {
+                            "href": "\/attendees"
+                        }
+                    }
+                }
+            ],
+            "_links": {
+                "self": {
+                    "href": "\/workshops\/803449f4-9a4c-4ecb-8ce4-cebc804fe70a"
+                },
+                "collection": {
+                    "href": "\/workshops"
+                }
+            }
+        }
+    ],
+    "total": 1,
+    "count": 1,
+    "_links": {
+        "self": {
+            "href": "\/attendees?page=1&size=10"
+        }
+    }
+}
diff --git a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_list_all_attendees with data set json__1.json b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_list_all_attendees with data set json__1.json
new file mode 100644
index 0000000..aef2fdc
--- /dev/null
+++ b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_list_all_attendees with data set json__1.json	
@@ -0,0 +1,22 @@
+{
+    "items": [
+        {
+            "identifier": "803449f4-9a4c-4ecb-8ce4-cebc804fe70a",
+            "firstname": "Jan",
+            "lastname": "Sch\u00e4dlich",
+            "email": "schaedlich.jan@gmail.com",
+            "workshops": [
+                {
+                    "identifier": "abba667a-96ae-4f75-9b71-97819b682e8d",
+                    "title": "RESTful Webservices in Symfony",
+                    "workshop_date": "2022-06-14",
+                    "attendees": [
+                        "Jan Sch\u00e4dlich"
+                    ]
+                }
+            ]
+        }
+    ],
+    "total": 1,
+    "count": 1
+}
diff --git a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 1st page, 3 items each__1.json b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 1st page, 3 items each__1.json
index d6dca91..c7a3368 100644
--- a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 1st page, 3 items each__1.json	
+++ b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 1st page, 3 items each__1.json	
@@ -5,61 +5,23 @@
             "firstname": "a",
             "lastname": "1",
             "email": "a1@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/4878f198-36ab-4fe3-8189-19662a9764fa"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         },
         {
             "identifier": "e942ce16-27c2-494f-9d93-03412da980c5",
             "firstname": "b",
             "lastname": "2",
             "email": "b2@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/e942ce16-27c2-494f-9d93-03412da980c5"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         },
         {
             "identifier": "4714fb8a-83d8-49af-abbf-7c68fc6c9656",
             "firstname": "c",
             "lastname": "3",
             "email": "c3@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/4714fb8a-83d8-49af-abbf-7c68fc6c9656"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         }
     ],
     "total": 5,
-    "count": 3,
-    "_links": {
-        "self": {
-            "href": "\/attendees?page=1&size=3"
-        },
-        "first": {
-            "href": "\/attendees?page=1&size=3"
-        },
-        "last": {
-            "href": "\/attendees?page=2&size=3"
-        },
-        "next": {
-            "href": "\/attendees?page=2&size=3"
-        }
-    }
+    "count": 3
 }
diff --git a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 1st page, 5 items each__1.json b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 1st page, 5 items each__1.json
index 894de6a..f6ffe29 100644
--- a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 1st page, 5 items each__1.json	
+++ b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 1st page, 5 items each__1.json	
@@ -5,82 +5,37 @@
             "firstname": "a",
             "lastname": "1",
             "email": "a1@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/4878f198-36ab-4fe3-8189-19662a9764fa"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         },
         {
             "identifier": "e942ce16-27c2-494f-9d93-03412da980c5",
             "firstname": "b",
             "lastname": "2",
             "email": "b2@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/e942ce16-27c2-494f-9d93-03412da980c5"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         },
         {
             "identifier": "4714fb8a-83d8-49af-abbf-7c68fc6c9656",
             "firstname": "c",
             "lastname": "3",
             "email": "c3@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/4714fb8a-83d8-49af-abbf-7c68fc6c9656"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         },
         {
             "identifier": "65445e8c-a6c6-4955-9eb2-5fb60d6a991e",
             "firstname": "d",
             "lastname": "4",
             "email": "d4@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/65445e8c-a6c6-4955-9eb2-5fb60d6a991e"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         },
         {
             "identifier": "3aacd688-5b81-4aba-a5ea-ac7668ba95b6",
             "firstname": "e",
             "lastname": "5",
             "email": "e5@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/3aacd688-5b81-4aba-a5ea-ac7668ba95b6"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         }
     ],
     "total": 5,
-    "count": 5,
-    "_links": {
-        "self": {
-            "href": "\/attendees?page=1&size=5"
-        }
-    }
+    "count": 5
 }
diff --git a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 2nd page, 3 items each__1.json b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 2nd page, 3 items each__1.json
index 4643d9e..dd26fbd 100644
--- a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 2nd page, 3 items each__1.json	
+++ b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 2nd page, 3 items each__1.json	
@@ -5,46 +5,16 @@
             "firstname": "d",
             "lastname": "4",
             "email": "d4@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/65445e8c-a6c6-4955-9eb2-5fb60d6a991e"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         },
         {
             "identifier": "3aacd688-5b81-4aba-a5ea-ac7668ba95b6",
             "firstname": "e",
             "lastname": "5",
             "email": "e5@test.de",
-            "workshops": [],
-            "_links": {
-                "self": {
-                    "href": "\/workshops\/3aacd688-5b81-4aba-a5ea-ac7668ba95b6"
-                },
-                "collection": {
-                    "href": "\/workshops"
-                }
-            }
+            "workshops": []
         }
     ],
     "total": 5,
-    "count": 2,
-    "_links": {
-        "self": {
-            "href": "\/attendees?page=2&size=3"
-        },
-        "first": {
-            "href": "\/attendees?page=1&size=3"
-        },
-        "last": {
-            "href": "\/attendees?page=2&size=3"
-        },
-        "prev": {
-            "href": "\/attendees?page=1&size=3"
-        }
-    }
+    "count": 2
 }
diff --git a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 2nd page, 5 items each__1.json b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 2nd page, 5 items each__1.json
index e6c1a1f..b985846 100644
--- a/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 2nd page, 5 items each__1.json	
+++ b/tests/Controller/Attendee/__snapshots__/ListControllerTest__test_it_should_paginate_attendees with data set show 2nd page, 5 items each__1.json	
@@ -1,13 +1,5 @@
 {
     "items": [],
     "total": 5,
-    "count": 0,
-    "_links": {
-        "self": {
-            "href": "\/attendees?page=2&size=5"
-        },
-        "prev": {
-            "href": "\/attendees?page=1&size=5"
-        }
-    }
+    "count": 0
 }
diff --git a/tests/Controller/Attendee/__snapshots__/ReadControllerTest__test_it_should_show_requested_attendee with data set haljson__1.json b/tests/Controller/Attendee/__snapshots__/ReadControllerTest__test_it_should_show_requested_attendee with data set haljson__1.json
new file mode 100644
index 0000000..2388fd4
--- /dev/null
+++ b/tests/Controller/Attendee/__snapshots__/ReadControllerTest__test_it_should_show_requested_attendee with data set haljson__1.json	
@@ -0,0 +1,32 @@
+{
+    "identifier": "17058af8-1b0f-4afe-910d-669b4bd0fd26",
+    "firstname": "Jan",
+    "lastname": "Sch\u00e4dlich",
+    "email": "schaedlich.jan@gmail.com",
+    "workshops": [
+        {
+            "identifier": "12bc7c60-7f77-41e0-90eb-9996a64a3b14",
+            "title": "RESTful Webservices in Symfony",
+            "workshop_date": "2022-06-14",
+            "attendees": [
+                "Jan Sch\u00e4dlich"
+            ],
+            "_links": {
+                "self": {
+                    "href": "\/attendees\/12bc7c60-7f77-41e0-90eb-9996a64a3b14"
+                },
+                "collection": {
+                    "href": "\/attendees"
+                }
+            }
+        }
+    ],
+    "_links": {
+        "self": {
+            "href": "\/workshops\/17058af8-1b0f-4afe-910d-669b4bd0fd26"
+        },
+        "collection": {
+            "href": "\/workshops"
+        }
+    }
+}
diff --git a/tests/Controller/Attendee/__snapshots__/ReadControllerTest__test_it_should_show_requested_attendee with data set json__1.json b/tests/Controller/Attendee/__snapshots__/ReadControllerTest__test_it_should_show_requested_attendee with data set json__1.json
new file mode 100644
index 0000000..763a24e
--- /dev/null
+++ b/tests/Controller/Attendee/__snapshots__/ReadControllerTest__test_it_should_show_requested_attendee with data set json__1.json	
@@ -0,0 +1,16 @@
+{
+    "identifier": "17058af8-1b0f-4afe-910d-669b4bd0fd26",
+    "firstname": "Jan",
+    "lastname": "Sch\u00e4dlich",
+    "email": "schaedlich.jan@gmail.com",
+    "workshops": [
+        {
+            "identifier": "12bc7c60-7f77-41e0-90eb-9996a64a3b14",
+            "title": "RESTful Webservices in Symfony",
+            "workshop_date": "2022-06-14",
+            "attendees": [
+                "Jan Sch\u00e4dlich"
+            ]
+        }
+    ]
+}
diff --git a/tests/Controller/Workshop/ListControllerTest.php b/tests/Controller/Workshop/ListControllerTest.php
index f31a41d..6a9fea0 100644
--- a/tests/Controller/Workshop/ListControllerTest.php
+++ b/tests/Controller/Workshop/ListControllerTest.php
@@ -8,15 +8,27 @@
 
 class ListControllerTest extends ApiTestCase
 {
-    public function test_it_should_list_all_workshops(): void
+    public static function provideHttpAcceptHeaderValues(): \Generator
+    {
+        yield 'json' => ['application/json'];
+        yield 'hal+json' => ['application/hal+json'];
+    }
+
+    /**
+     * @dataProvider provideHttpAcceptHeaderValues
+     */
+    public function test_it_should_list_all_workshops(string $httpAcceptHeaderValue): void
     {
         $this->loadFixtures([
             __DIR__.'/fixtures/list_workshop.yaml',
         ]);
 
-        $this->browser->request('GET', '/workshops');
+        $this->browser->request('GET', '/workshops', [], [], [
+            'HTTP_ACCEPT' => $httpAcceptHeaderValue,
+        ]);
 
         static::assertResponseIsSuccessful();
+        static::assertStringContainsString($httpAcceptHeaderValue, $this->browser->getResponse()->headers->get('Content-Type'));
 
         $this->assertMatchesJsonSnapshot($this->browser->getResponse()->getContent());
     }
diff --git a/tests/Controller/Workshop/ReadControllerTest.php b/tests/Controller/Workshop/ReadControllerTest.php
index 29a1352..70504e4 100644
--- a/tests/Controller/Workshop/ReadControllerTest.php
+++ b/tests/Controller/Workshop/ReadControllerTest.php
@@ -8,15 +8,27 @@
 
 class ReadControllerTest extends ApiTestCase
 {
-    public function test_it_should_show_requested_workshop(): void
+    public static function provideHttpAcceptHeaderValues(): \Generator
+    {
+        yield 'json' => ['application/json'];
+        yield 'hal+json' => ['application/hal+json'];
+    }
+
+    /**
+     * @dataProvider provideHttpAcceptHeaderValues
+     */
+    public function test_it_should_show_requested_workshop(string $httpAcceptHeaderValue): void
     {
         $this->loadFixtures([
             __DIR__.'/fixtures/read_workshop.yaml',
         ]);
 
-        $this->browser->request('GET', '/workshops/8acf8f2b-95c1-46e1-85a4-ea6ff88081ce');
+        $this->browser->request('GET', '/workshops/8acf8f2b-95c1-46e1-85a4-ea6ff88081ce', [], [], [
+            'HTTP_ACCEPT' => $httpAcceptHeaderValue,
+        ]);
 
         static::assertResponseIsSuccessful();
+        static::assertStringContainsString($httpAcceptHeaderValue, $this->browser->getResponse()->headers->get('Content-Type'));
 
         $this->assertMatchesJsonSnapshot($this->browser->getResponse()->getContent());
     }
diff --git a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_list_all_workshops with data set haljson__1.json b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_list_all_workshops with data set haljson__1.json
new file mode 100644
index 0000000..ce823b4
--- /dev/null
+++ b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_list_all_workshops with data set haljson__1.json	
@@ -0,0 +1,43 @@
+{
+    "items": [
+        {
+            "identifier": "ef6e13ef-f601-4e74-bae8-bdf8f41cd8db",
+            "title": "RESTful Webservices in Symfony",
+            "workshop_date": "2022-06-14",
+            "attendees": [
+                {
+                    "identifier": "2a451d60-2fef-437b-838e-10edb2ade8eb",
+                    "firstname": "Jan",
+                    "lastname": "Sch\u00e4dlich",
+                    "email": "schaedlich.jan@gmail.com",
+                    "workshops": [
+                        "RESTful Webservices in Symfony"
+                    ],
+                    "_links": {
+                        "self": {
+                            "href": "\/workshops\/2a451d60-2fef-437b-838e-10edb2ade8eb"
+                        },
+                        "collection": {
+                            "href": "\/workshops"
+                        }
+                    }
+                }
+            ],
+            "_links": {
+                "self": {
+                    "href": "\/attendees\/ef6e13ef-f601-4e74-bae8-bdf8f41cd8db"
+                },
+                "collection": {
+                    "href": "\/attendees"
+                }
+            }
+        }
+    ],
+    "total": 1,
+    "count": 1,
+    "_links": {
+        "self": {
+            "href": "\/workshops?page=1&size=10"
+        }
+    }
+}
diff --git a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_list_all_workshops with data set json__1.json b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_list_all_workshops with data set json__1.json
new file mode 100644
index 0000000..46094b5
--- /dev/null
+++ b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_list_all_workshops with data set json__1.json	
@@ -0,0 +1,22 @@
+{
+    "items": [
+        {
+            "identifier": "ef6e13ef-f601-4e74-bae8-bdf8f41cd8db",
+            "title": "RESTful Webservices in Symfony",
+            "workshop_date": "2022-06-14",
+            "attendees": [
+                {
+                    "identifier": "2a451d60-2fef-437b-838e-10edb2ade8eb",
+                    "firstname": "Jan",
+                    "lastname": "Sch\u00e4dlich",
+                    "email": "schaedlich.jan@gmail.com",
+                    "workshops": [
+                        "RESTful Webservices in Symfony"
+                    ]
+                }
+            ]
+        }
+    ],
+    "total": 1,
+    "count": 1
+}
diff --git a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 1st page, 3 items each__1.json b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 1st page, 3 items each__1.json
index db902d7..5fa4b11 100644
--- a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 1st page, 3 items each__1.json	
+++ b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 1st page, 3 items each__1.json	
@@ -4,59 +4,21 @@
             "identifier": "775ead00-7f50-466f-b89d-73150c9adfc8",
             "title": "a",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/775ead00-7f50-466f-b89d-73150c9adfc8"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         },
         {
             "identifier": "8b84bf4a-a8e9-436a-85ce-2f5df8f8a3a2",
             "title": "b",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/8b84bf4a-a8e9-436a-85ce-2f5df8f8a3a2"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         },
         {
             "identifier": "531b95c9-05c5-49ac-98ec-e0263f35d83e",
             "title": "c",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/531b95c9-05c5-49ac-98ec-e0263f35d83e"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         }
     ],
     "total": 5,
-    "count": 3,
-    "_links": {
-        "self": {
-            "href": "\/workshops?page=1&size=3"
-        },
-        "first": {
-            "href": "\/workshops?page=1&size=3"
-        },
-        "last": {
-            "href": "\/workshops?page=2&size=3"
-        },
-        "next": {
-            "href": "\/workshops?page=2&size=3"
-        }
-    }
+    "count": 3
 }
diff --git a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 1st page, 5 items each__1.json b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 1st page, 5 items each__1.json
index 3c38d22..53fee32 100644
--- a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 1st page, 5 items each__1.json	
+++ b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 1st page, 5 items each__1.json	
@@ -4,78 +4,33 @@
             "identifier": "775ead00-7f50-466f-b89d-73150c9adfc8",
             "title": "a",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/775ead00-7f50-466f-b89d-73150c9adfc8"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         },
         {
             "identifier": "8b84bf4a-a8e9-436a-85ce-2f5df8f8a3a2",
             "title": "b",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/8b84bf4a-a8e9-436a-85ce-2f5df8f8a3a2"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         },
         {
             "identifier": "531b95c9-05c5-49ac-98ec-e0263f35d83e",
             "title": "c",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/531b95c9-05c5-49ac-98ec-e0263f35d83e"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         },
         {
             "identifier": "d0e2cbfd-eff0-4025-90fb-3350aada0939",
             "title": "d",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/d0e2cbfd-eff0-4025-90fb-3350aada0939"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         },
         {
             "identifier": "9aa6e731-6058-4f2c-9081-aadeb15db35e",
             "title": "e",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/9aa6e731-6058-4f2c-9081-aadeb15db35e"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         }
     ],
     "total": 5,
-    "count": 5,
-    "_links": {
-        "self": {
-            "href": "\/workshops?page=1&size=5"
-        }
-    }
+    "count": 5
 }
diff --git a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 2nd page, 3 items each__1.json b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 2nd page, 3 items each__1.json
index 55e4f54..349d498 100644
--- a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 2nd page, 3 items each__1.json	
+++ b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 2nd page, 3 items each__1.json	
@@ -4,45 +4,15 @@
             "identifier": "d0e2cbfd-eff0-4025-90fb-3350aada0939",
             "title": "d",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/d0e2cbfd-eff0-4025-90fb-3350aada0939"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         },
         {
             "identifier": "9aa6e731-6058-4f2c-9081-aadeb15db35e",
             "title": "e",
             "workshop_date": "2021-12-07",
-            "attendees": [],
-            "_links": {
-                "self": {
-                    "href": "\/attendees\/9aa6e731-6058-4f2c-9081-aadeb15db35e"
-                },
-                "collection": {
-                    "href": "\/attendees"
-                }
-            }
+            "attendees": []
         }
     ],
     "total": 5,
-    "count": 2,
-    "_links": {
-        "self": {
-            "href": "\/workshops?page=2&size=3"
-        },
-        "first": {
-            "href": "\/workshops?page=1&size=3"
-        },
-        "last": {
-            "href": "\/workshops?page=2&size=3"
-        },
-        "prev": {
-            "href": "\/workshops?page=1&size=3"
-        }
-    }
+    "count": 2
 }
diff --git a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 2nd page, 5 items each__1.json b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 2nd page, 5 items each__1.json
index eab1cbb..b985846 100644
--- a/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 2nd page, 5 items each__1.json	
+++ b/tests/Controller/Workshop/__snapshots__/ListControllerTest__test_it_should_paginate_workshops with data set show 2nd page, 5 items each__1.json	
@@ -1,13 +1,5 @@
 {
     "items": [],
     "total": 5,
-    "count": 0,
-    "_links": {
-        "self": {
-            "href": "\/workshops?page=2&size=5"
-        },
-        "prev": {
-            "href": "\/workshops?page=1&size=5"
-        }
-    }
+    "count": 0
 }
diff --git a/tests/Controller/Workshop/__snapshots__/ReadControllerTest__test_it_should_show_requested_workshop with data set haljson__1.json b/tests/Controller/Workshop/__snapshots__/ReadControllerTest__test_it_should_show_requested_workshop with data set haljson__1.json
new file mode 100644
index 0000000..bd4a30c
--- /dev/null
+++ b/tests/Controller/Workshop/__snapshots__/ReadControllerTest__test_it_should_show_requested_workshop with data set haljson__1.json	
@@ -0,0 +1,32 @@
+{
+    "identifier": "8acf8f2b-95c1-46e1-85a4-ea6ff88081ce",
+    "title": "RESTful Webservices in Symfony",
+    "workshop_date": "2022-06-14",
+    "attendees": [
+        {
+            "identifier": "36ffcf19-7560-4ead-8d8e-3c40cf169784",
+            "firstname": "Jan",
+            "lastname": "Sch\u00e4dlich",
+            "email": "schaedlich.jan@gmail.com",
+            "workshops": [
+                "RESTful Webservices in Symfony"
+            ],
+            "_links": {
+                "self": {
+                    "href": "\/workshops\/36ffcf19-7560-4ead-8d8e-3c40cf169784"
+                },
+                "collection": {
+                    "href": "\/workshops"
+                }
+            }
+        }
+    ],
+    "_links": {
+        "self": {
+            "href": "\/attendees\/8acf8f2b-95c1-46e1-85a4-ea6ff88081ce"
+        },
+        "collection": {
+            "href": "\/attendees"
+        }
+    }
+}
diff --git a/tests/Controller/Workshop/__snapshots__/ReadControllerTest__test_it_should_show_requested_workshop with data set json__1.json b/tests/Controller/Workshop/__snapshots__/ReadControllerTest__test_it_should_show_requested_workshop with data set json__1.json
new file mode 100644
index 0000000..0bb7af6
--- /dev/null
+++ b/tests/Controller/Workshop/__snapshots__/ReadControllerTest__test_it_should_show_requested_workshop with data set json__1.json	
@@ -0,0 +1,16 @@
+{
+    "identifier": "8acf8f2b-95c1-46e1-85a4-ea6ff88081ce",
+    "title": "RESTful Webservices in Symfony",
+    "workshop_date": "2022-06-14",
+    "attendees": [
+        {
+            "identifier": "36ffcf19-7560-4ead-8d8e-3c40cf169784",
+            "firstname": "Jan",
+            "lastname": "Sch\u00e4dlich",
+            "email": "schaedlich.jan@gmail.com",
+            "workshops": [
+                "RESTful Webservices in Symfony"
+            ]
+        }
+    ]
+}