diff --git a/catalyst/api-bundle/Controller/APIController.php b/catalyst/api-bundle/Controller/APIController.php
index fc38e32b..7f359680 100644
--- a/catalyst/api-bundle/Controller/APIController.php
+++ b/catalyst/api-bundle/Controller/APIController.php
@@ -2,6 +2,40 @@
 
 namespace Catalyst\APIBundle\Controller;
 
-interface APIController
+use Symfony\Bundle\FrameworkBundle\Controller\Controller;
+use Symfony\Component\HttpFoundation\Request;
+
+abstract class APIController extends Controller
 {
+    protected function checkRequiredParameters(Request $req, $params = [])
+    {
+        $missing = [];
+
+        // check if parameters are there
+        foreach ($params as $param)
+        {
+            if ($req->getMethod() == 'GET')
+            {
+                $check = $req->query->get($param);
+                if (empty($check))
+                    $missing[] = $param;
+            }
+            // else if ($req->getMethod() == 'POST')
+            else
+            {
+                $check = $req->request->get($param);
+                if (empty($check))
+                    $missing[] = $param;
+            }
+        }
+
+        // check missing parameters
+        if (count($missing) > 0)
+        {
+            $miss_string = implode(', ', $missing);
+            return 'Missing required parameter(s): ' . $miss_string;
+        }
+
+        return false;
+    }
 }
diff --git a/src/Controller/CAPI/BatteryController.php b/src/Controller/CAPI/BatteryController.php
index f99d0ad5..e42a220b 100644
--- a/src/Controller/CAPI/BatteryController.php
+++ b/src/Controller/CAPI/BatteryController.php
@@ -11,7 +11,7 @@ use Catalyst\APIBundle\Response\APIResponse;
 use App\Entity\BatteryModel;
 use App\Entity\BatterySize;
 
-class BatteryController extends Controller implements APIController
+class BatteryController extends APIController
 {
     public function getModels(EntityManagerInterface $em)
     {
diff --git a/src/Controller/CAPI/TestController.php b/src/Controller/CAPI/TestController.php
index 0143166a..e1a5ea08 100644
--- a/src/Controller/CAPI/TestController.php
+++ b/src/Controller/CAPI/TestController.php
@@ -8,7 +8,7 @@ use Doctrine\ORM\Query;
 use Catalyst\APIBundle\Controller\APIController;
 use Catalyst\APIBundle\Response\APIResponse;
 
-class TestController extends Controller implements APIController
+class TestController extends APIController
 {
     public function test()
     {
diff --git a/src/Controller/CAPI/VehicleController.php b/src/Controller/CAPI/VehicleController.php
index 67527bb3..0d9ab174 100644
--- a/src/Controller/CAPI/VehicleController.php
+++ b/src/Controller/CAPI/VehicleController.php
@@ -11,7 +11,7 @@ use Catalyst\APIBundle\Response\APIResponse;
 use App\Entity\Vehicle;
 use App\Entity\VehicleManufacturer;
 
-class VehicleController extends Controller implements APIController
+class VehicleController extends APIController
 {
     public function getManufacturers(EntityManagerInterface $em)
     {
diff --git a/src/Controller/CAPI/WarrantyController.php b/src/Controller/CAPI/WarrantyController.php
index 0a6e8ff8..c77b29e4 100644
--- a/src/Controller/CAPI/WarrantyController.php
+++ b/src/Controller/CAPI/WarrantyController.php
@@ -17,40 +17,8 @@ use App\Ramcar\WarrantyClass;
 use App\Ramcar\WarrantyStatus;
 use DateTime;
 
-class WarrantyController extends Controller implements APIController
+class WarrantyController extends APIController
 {
-    protected function checkRequiredParameters(Request $req, $params = [])
-    {
-        $missing = [];
-
-        // check if parameters are there
-        foreach ($params as $param)
-        {
-            if ($req->getMethod() == 'GET')
-            {
-                $check = $req->query->get($param);
-                if (empty($check))
-                    $missing[] = $param;
-            }
-            // else if ($req->getMethod() == 'POST')
-            else
-            {
-                $check = $req->request->get($param);
-                if (empty($check))
-                    $missing[] = $param;
-            }
-        }
-
-        // check missing parameters
-        if (count($missing) > 0)
-        {
-            $miss_string = implode(', ', $missing);
-            return 'Missing required parameter(s): ' . $miss_string;
-        }
-
-        return false;
-    }
-
     protected function cleanSerial($serial)
     {
         return trim(strtoupper($serial));