diff --git a/README.md b/README.md
index 24bfdf3..76c9c2d 100644
--- a/README.md
+++ b/README.md
@@ -34,9 +34,9 @@ The list of endpoints then looks like the following:
 It is also possible to obtain the JSON representation of a supported entity:
 
   // For a given $entity object.
-  $json_output = \Drupal::service('jsonapi.entity.to_json', ['resource' => $entity])->json();
+  $json_output = \Drupal::service('jsonapi.entity.to_json')->json($entity);
 
 Should it be needed, the raw string itself can be obtained:
 
   // For a given $entity object.
-  $json_output = \Drupal::service('jsonapi.entity.to_json', ['resource' => $entity])->raw();
+  $raw_output = \Drupal::service('jsonapi.entity.to_json')->raw($entity);
diff --git a/src/Controller/ToJson.php b/src/Controller/ToJson.php
index 6ea207f..a41c275 100644
--- a/src/Controller/ToJson.php
+++ b/src/Controller/ToJson.php
@@ -2,50 +2,61 @@
 
 namespace Drupal\jsonapi\Controller;
 
-use Drupal\Component\Serialization\Json;
-use Drupal\Core\Cache\CacheableMetadata;
-use Drupal\Core\Controller\ControllerBase;
-use Drupal\Core\Entity\EntityInterface;
+use \Drupal\Component\Serialization\Json;
+use \Drupal\Core\Controller\ControllerBase;
+use \Drupal\Core\Entity\EntityInterface;
+use \Symfony\Component\HttpFoundation\Request;
+use \Symfony\Component\HttpKernel\HttpKernelInterface;
 
 /**
  * Provide JSON output for a given object.
  */
 class ToJson extends ControllerBase {
 
-  /** @var object */
-  // protected $entity;
-
-  /**
-   * {@inheritDoc}
-   */
-  // public function __construct(EntityInterface $entity) {
-  //   $this->entity = $entity;
-  // }
-
   /**
    * Return the requested entity as a JSON object.
    *
-   * @return Drupal\Component\Serialization\Json
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   *   The entity to generate the JSON from.
+   * @param array $options
+   *   Optional arguments to pass to the HTTP Kernel request.
+   *
+   * @return \Drupal\Component\Serialization\Json
    *   The requested resource in JSON form.
    */
-  public function json($entity) {
-    return Json::decode($this->raw($entity));
+  public function json(EntityInterface $entity, array $options = []) {
+    return Json::decode($this->raw($entity, $options));
   }
 
   /**
    * Return the requested entity as a raw string.
    *
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   *   The entity to generate the JSON from.
+   * @param array $options
+   *   Optional arguments to pass to the HTTP Kernel request.
+   *
    * @return string
    *   The raw JSON string of the requested resource.
    */
-  public function raw($entity) {
-    $format = 'api_json';
-    $context = [
-      'account' => \Drupal::currentUser(),
-      'cacheable_metadata' => new CacheableMetadata(),
-    ];
-    return \Drupal::service('serializer.normalizer.entity.jsonapi')
-      ->normalize($entity, $format, $context)
-      ->rasterizeValue();
+  public function raw(EntityInterface $entity, array $options = []) {
+    $resource = "{$entity->getEntityTypeId()}/{$entity->bundle()}/{$entity->uuid()}";
+
+    /** @var \Symfony\Component\HttpKernel\HttpKernelInterface $kernel */
+    $kernel = \Drupal::service('http_kernel.basic');
+
+    $request = Request::create('/jsonapi/' . $resource, 'GET', $options + ['_format' => 'api_json']);
+
+    // @todo Drop this hack when https://www.drupal.org/node/2613044 is done.
+    $previous_request = \Drupal::requestStack()->getCurrentRequest();
+
+    // @todo Find a nicer implementation with maybe less layers involved.
+    $response = $kernel->handle($request, HttpKernelInterface::SUB_REQUEST, TRUE);
+
+    \Drupal::requestStack()->push($previous_request);
+
+    // @todo How to take into account cacheability metadata.
+    return $response->getContent();
   }
+
 }
diff --git a/tests/src/Functional/JsonApiFunctionalToJsonTest.php b/tests/src/Functional/JsonApiFunctionalToJsonTest.php
index 47d7b3b..b783091 100644
--- a/tests/src/Functional/JsonApiFunctionalToJsonTest.php
+++ b/tests/src/Functional/JsonApiFunctionalToJsonTest.php
@@ -30,10 +30,11 @@ protected function setUp() {
     parent::setUp();
 
     drupal_flush_all_caches();
+    $this->drupalGet('');
   }
 
   /**
-   *  Check the output of the system service.
+   * Check the output of the system service.
    */
   public function testService() {
     $node = $this->createNode();