diff --git a/lib/Controller/CardApiController.php b/lib/Controller/CardApiController.php
index c754dd84c..f91f97250 100644
--- a/lib/Controller/CardApiController.php
+++ b/lib/Controller/CardApiController.php
@@ -28,6 +28,9 @@
  use OCP\AppFramework\Http\DataResponse;
  use OCP\IRequest;
 
+ use OCA\Deck\Controller\Helper\ApiHelper;
+ use OCA\Deck\Service\BoardService;
+ use OCA\Deck\Service\StackService;
  use OCA\Deck\Service\CardService;
 
  /**
@@ -37,7 +40,10 @@
  */
 class CardApiController extends ApiController {
 	private $cardService;
+	private $boardService;
+	private $stackService;
 	private $userId;
+	private $apiHelper;
 
 	/**
 	 * @param string $appName
@@ -45,10 +51,13 @@ class CardApiController extends ApiController {
 	 * @param CardService $service
 	 * @param $userId
 	 */
-	public function __construct($appName, IRequest $request, CardService $cardService, $userId) {
+	public function __construct($appName, IRequest $request, CardService $cardService, BoardService $boardService, StackService $stackService, $userId) {
 		parent::__construct($appName, $request);
+		$this->boardService = $boardService;
 		$this->cardService = $cardService;
+		$this->stackService = $stackService;
 		$this->userId = $userId;
+		$this->apiHelper = new ApiHelper();
 	}
 
 	/**
@@ -58,14 +67,15 @@ class CardApiController extends ApiController {
 	 *
 	 * Get a specific card.
 	 */
-	public function get() {		
-
-		if (is_numeric($this->request->params['boardId']) === false) {
-			return new DataResponse('board id must be a number', HTTP::STATUS_BAD_REQUEST);
+	public function get() {
+		$boardError = $this->apiHelper->boardHasError($this->request->params['boardId'], $this->boardService);
+		if ($boardError) {
+			return new DataResponse($boardError['message'], $boardError['status']);
 		}
 
-		if (is_numeric($this->request->params['stackId']) === false) {
-			return new DataResponse('stack id must be a number', HTTP::STATUS_BAD_REQUEST);
+		$stackError = $this->apiHelper->entityHasError($this->request->params['stackId'], 'stack', $this->stackService);		
+		if ($stackError) {
+			return new DataResponse($stackError['message'], $stackError['status']);
 		}
 
 		if (is_numeric($this->request->params['cardId']) === false) {
@@ -94,12 +104,14 @@ class CardApiController extends ApiController {
 	 */
 	public function create($title, $type = 'plain', $order = 999) {
 
-		if (is_numeric($this->request->params['boardId']) === false) {
-			return new DataResponse('board id must be a number', HTTP::STATUS_BAD_REQUEST);
+		$boardError = $this->apiHelper->boardHasError($this->request->params['boardId'], 'board', $this->boardService);
+		if ($boardError) {
+			return new DataResponse($boardError['message'], $boardError['status']);
 		}
 
-		if (is_numeric($this->request->params['stackId']) === false) {
-			return new DataResponse('stack id must be a number', HTTP::STATUS_BAD_REQUEST);
+		$stackError = $this->apiHelper->entityHasError($this->request->params['stackId'], 'stack', $this->stackService);		
+		if ($stackError) {
+			return new DataResponse($stackError['message'], $stackError['status']);
 		}
 
 		if ($title === false || $title === null) {
@@ -136,17 +148,19 @@ class CardApiController extends ApiController {
 	 */
 	public function update($title, $type, $order, $description = null, $duedate = null, $archive = false, $assignedUserId = 0) {
 
+		$boardError = $this->apiHelper->boardHasError($this->request->params['boardId'], 'board', $this->boardService);
+		if ($boardError) {
+			return new DataResponse($boardError['message'], $boardError['status']);
+		}
+
+		$stackError = $this->apiHelper->entityHasError($this->request->params['stackId'], 'stack', $this->stackService);		
+		if ($stackError) {
+			return new DataResponse($stackError['message'], $stackError['status']);
+		}
+
 		if (is_numeric($this->request->params['cardId']) === false) {
 			return new DataResponse('card id must be a number', HTTP::STATUS_BAD_REQUEST);
-		}
-
-		if (is_numeric($this->request->params['stackId']) === false) {
-			return new DataResponse('stack id must be a number', HTTP::STATUS_BAD_REQUEST);
-		}
-
-		if (is_numeric($this->request->params['boardId']) === false) {
-			return new DataResponse('board id must be a number', HTTP::STATUS_BAD_REQUEST);
-		}
+		}		
 
 		if ($title === false || $title === null) {
 			return new DataResponse('title must be provided', HTTP::STATUS_BAD_REQUEST);
@@ -203,17 +217,19 @@ class CardApiController extends ApiController {
 	 */
 	public function delete() {
 
+		$boardError = $this->apiHelper->boardHasError($this->request->params['boardId'], 'board', $this->boardService);
+		if ($boardError) {
+			return new DataResponse($boardError['message'], $boardError['status']);
+		}
+
+		$stackError = $this->apiHelper->entityHasError($this->request->params['stackId'], 'stack', $this->stackService);		
+		if ($stackError) {
+			return new DataResponse($stackError['message'], $stackError['status']);
+		}
+
 		if (is_numeric($this->request->params['cardId']) === false) {
 			return new DataResponse('card id must be a number', HTTP::STATUS_BAD_REQUEST);
-		}
-
-		if (is_numeric($this->request->params['stackId']) === false) {
-			return new DataResponse('stack id must be a number', HTTP::STATUS_BAD_REQUEST);
-		}
-
-		if (is_numeric($this->request->params['boardId']) === false) {
-			return new DataResponse('board id must be a number', HTTP::STATUS_BAD_REQUEST);
-		}
+		}		
 
 		try {
 			$card = $this->cardService->delete($this->request->params['cardId']);
diff --git a/lib/Controller/Helper/ApiHelper.php b/lib/Controller/Helper/ApiHelper.php
index f8f16828b..8785dcbe0 100644
--- a/lib/Controller/Helper/ApiHelper.php
+++ b/lib/Controller/Helper/ApiHelper.php
@@ -28,17 +28,35 @@ use OCP\AppFramework\Http;
 
 class ApiHelper {
 
-	public static function entityHasError($entityId, $entityName, $service) {				
-		if (is_numeric($entityId) === false) {
-			$error['message'] = $entityName . ' id must be a number';
+	public static function boardHasError($boardId, $boardService) {				
+		if (is_numeric($boardId) === false) {
+			$error['message'] = 'board id must be a number';
 			$error['status'] = HTTP::STATUS_BAD_REQUEST;
 			return $error;
 		}
 
-		$entity = $service->find($entityId);
+		$board = $boardService->find($boardId);
 
-		if ($entity === false || $entity === null) {
-			$error['message'] = 'Board does not exist';
+		if ($board === false || $board === null) {
+			$error['message'] = 'board does not exist';
+			$error['status'] = HTTP::STATUS_NOT_FOUND;
+			return $error;
+		}
+
+		return false;
+	}
+
+	public static function stackHasError($stackId, $stackService) {
+		if (is_numeric($stackId) === false) {
+			$error['message'] = 'board id must be a number';
+			$error['status'] = HTTP::STATUS_BAD_REQUEST;
+			return $error;
+		}
+
+		$stack = $stackService->find($stackId);
+
+		if ($stack === false || $stack === null) {
+			$error['message'] = 'stack does not exist';
 			$error['status'] = HTTP::STATUS_NOT_FOUND;
 			return $error;
 		}
diff --git a/lib/Controller/StackApiController.php b/lib/Controller/StackApiController.php
index cba2383ed..e00fbfa85 100644
--- a/lib/Controller/StackApiController.php
+++ b/lib/Controller/StackApiController.php
@@ -66,7 +66,7 @@ class StackApiController extends ApiController {
 	 * Return all of the stacks in the specified board.
 	 */
 	public function index() {		
-		$boardError = $this->apiHelper->entityHasError( $this->request->params['boardId'], 'board', $this->boardService );		
+		$boardError = $this->apiHelper->boardHasError( $this->request->params['boardId'], $this->boardService );		
 
 		if ($boardError) {
 			return new DataResponse($boardError['message'], $boardError['status']);
@@ -95,7 +95,7 @@ class StackApiController extends ApiController {
 	 */
 	public function create($title, $order) {		
 
-		$boardError = $this->apiHelper->entityHasError( $this->request->params['boardId'], 'board', $this->boardService );
+		$boardError = $this->apiHelper->boardHasError( $this->request->params['boardId'], $this->boardService );
 
 		if ($boardError) {
 			return new DataResponse($boardError['message'], $boardError['status']);
@@ -127,7 +127,7 @@ class StackApiController extends ApiController {
 	 */
 	public function update($title, $order) {
 		
-		$boardError = $this->apiHelper->entityHasError( $this->request->params['boardId'], 'board', $this->boardService );
+		$boardError = $this->apiHelper->boardHasError( $this->request->params['boardId'], $this->boardService );
 
 		if ($boardError) {
 			return new DataResponse($boardError['message'], $boardError['status']);
@@ -163,7 +163,7 @@ class StackApiController extends ApiController {
 	 */
 	public function delete() {
 
-		$boardError = $this->apiHelper->entityHasError( $this->request->params['boardId'], 'board', $this->boardService );
+		$boardError = $this->apiHelper->boardHasError( $this->request->params['boardId'], $this->boardService );
 
 		if ($boardError) {
 			return new DataResponse($boardError['message'], $boardError['status']);
diff --git a/lib/Service/StackService.php b/lib/Service/StackService.php
index b64766e79..72211f730 100644
--- a/lib/Service/StackService.php
+++ b/lib/Service/StackService.php
@@ -89,6 +89,10 @@ class StackService {
 		}
 	}
 
+	public function find($stackId) {
+		throw new \Exception('Not yet implemented');
+	}
+
 	public function findAll($boardId) {
 		$this->permissionService->checkPermission(null, $boardId, Acl::PERMISSION_READ);
 		$stacks = $this->stackMapper->findAll($boardId);