diff --git a/api/modules/session/controllers/SessionController.php b/api/modules/session/controllers/SessionController.php
index e00b3d8..d95d581 100644
--- a/api/modules/session/controllers/SessionController.php
+++ b/api/modules/session/controllers/SessionController.php
@@ -34,19 +34,18 @@ class SessionController extends Controller {
     }
 
     /**
-     * @return array
      * @throws ForbiddenOperationException
      * @throws IllegalArgumentException
      */
-    public function actionJoin(): array {
-        Yii::$app->response->format = Response::FORMAT_JSON;
-
+    public function actionJoin(Response $response): void {
         $data = Yii::$app->request->post();
         $protocol = new ModernJoin($data['accessToken'] ?? '', $data['selectedProfile'] ?? '', $data['serverId'] ?? '');
         $joinForm = new JoinForm($protocol);
         $joinForm->join(); // will throw an exception in case of any error
 
-        return ['id' => 'OK'];
+        $response->statusCode = 204;
+        $response->format = Response::FORMAT_RAW;
+        $response->content = '';
     }
 
     public function actionJoinLegacy(): string {
diff --git a/api/tests/functional/_steps/SessionServerSteps.php b/api/tests/functional/_steps/SessionServerSteps.php
index adec3a0..346f127 100644
--- a/api/tests/functional/_steps/SessionServerSteps.php
+++ b/api/tests/functional/_steps/SessionServerSteps.php
@@ -30,7 +30,7 @@ class SessionServerSteps extends FunctionalTester {
                 'serverId' => $serverId,
             ]);
 
-            $this->canSeeResponseContainsJson(['id' => 'OK']);
+            $this->seeResponseCodeIs(204);
         }
 
         return [$username, $serverId];
diff --git a/api/tests/functional/sessionserver/JoinCest.php b/api/tests/functional/sessionserver/JoinCest.php
index 76391dd..fd7fddb 100644
--- a/api/tests/functional/sessionserver/JoinCest.php
+++ b/api/tests/functional/sessionserver/JoinCest.php
@@ -150,12 +150,9 @@ class JoinCest {
         ]);
     }
 
-    private function expectSuccessResponse(FunctionalTester $I) {
-        $I->seeResponseCodeIs(200);
-        $I->seeResponseIsJson();
-        $I->canSeeResponseContainsJson([
-            'id' => 'OK',
-        ]);
+    private function expectSuccessResponse(FunctionalTester $I): void {
+        $I->seeResponseCodeIs(204);
+        $I->canSeeResponseEquals('');
     }
 
 }