diff --git a/src/Controller/Admin/CheckinAction.php b/src/Controller/Admin/CheckinAction.php
new file mode 100644
index 0000000..22f4056
--- /dev/null
+++ b/src/Controller/Admin/CheckinAction.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace App\Controller\Admin;
+
+use App\Repository\TicketRepository;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Attribute\Route;
+
+class CheckinAction extends AbstractController
+{
+    public function __construct(
+        private TicketRepository $ticketRepository,
+        private EntityManagerInterface $entityManager,
+    ) {
+    }
+
+    #[Route(path: '/admin/checkin', name: 'admin_checkin', methods: Request::METHOD_POST)]
+    public function __invoke(Request $request): Response
+    {
+        $entityId = $request->query->get('entityId');
+
+        if (!$entityId || !$ticket = $this->ticketRepository->findOneById($entityId)) {
+            noty()->error('Ein Fehler ist aufgetreten.');
+
+            return $this->redirect($request->get('referer'));
+        }
+
+        $ticket->setCheckedIn(true);
+        $this->entityManager->flush();
+
+        return $this->redirect($request->headers->get('referer'));
+    }
+}
\ No newline at end of file
diff --git a/src/Controller/Admin/TicketCrudController.php b/src/Controller/Admin/TicketCrudController.php
index 1b87949..af34e44 100644
--- a/src/Controller/Admin/TicketCrudController.php
+++ b/src/Controller/Admin/TicketCrudController.php
@@ -34,7 +34,8 @@ class TicketCrudController extends AbstractCrudController
             ->formatValue(fn(Customer $customer) => $customer->getEmail())
             ->hideOnForm();
 
-        yield BooleanField::new('checkedIn', '')->setTemplatePath('admin/checked_in.html.twig');
+        yield BooleanField::new('checkedIn', '')
+            ->setTemplatePath('admin/checked_in.html.twig');
     }
 
 
diff --git a/src/Repository/TicketRepository.php b/src/Repository/TicketRepository.php
index cd6e338..3e5a0ce 100644
--- a/src/Repository/TicketRepository.php
+++ b/src/Repository/TicketRepository.php
@@ -9,6 +9,7 @@ use Doctrine\Persistence\ManagerRegistry;
 
 /**
  * @extends ServiceEntityRepository<Ticket>
+ * @method Ticket|null findOneById(int $entityId)
  */
 class TicketRepository extends ServiceEntityRepository
 {
diff --git a/src/Twig/Environment.php b/src/Twig/Environment.php
index 8f363be..96766ad 100644
--- a/src/Twig/Environment.php
+++ b/src/Twig/Environment.php
@@ -2,6 +2,7 @@
 
 namespace App\Twig;
 
+use EasyCorp\Bundle\EasyAdminBundle\Dto\FieldDto;
 use Twig\Extension\AbstractExtension;
 use Twig\TwigFunction;
 
@@ -9,11 +10,22 @@ class Environment extends AbstractExtension
 {
     public function getFunctions(): array
     {
-        return [new TwigFunction('env', $this->getVar(...))];
+        return [
+            new TwigFunction('env', $this->getVar(...)),
+            new TwigFunction('entityId', $this->getEntityId(...)),
+        ];
     }
 
     public function getVar(string $name): string
     {
         return $_ENV[$name];
     }
+
+    public function getEntityId(FieldDto $field): string
+    {
+        $url = $field->getCustomOption('toggleUrl');
+        preg_match('/entityId=(\d+)/', $url, $matches);
+
+        return $matches[1];
+    }
 }
\ No newline at end of file
diff --git a/templates/admin/checked_in.html.twig b/templates/admin/checked_in.html.twig
index ca79db0..24a928c 100644
--- a/templates/admin/checked_in.html.twig
+++ b/templates/admin/checked_in.html.twig
@@ -1,6 +1,7 @@
 {% if not field.value %}
-<button data-controller="checkin" data-id="">Einchecken</button>
-    {{ dump(field) }}
+    <form action="{{ path('admin_checkin', {'entityId': entityId(field)}) }}" method="post">
+        <button type="submit">Einchecken</button>
+    </form>
 {% else %}
-<button disabled>Eingechecked</button>
-{% endif %}
\ No newline at end of file
+<button disabled>Eingecheckt</button>
+{% endif %}