diff --git a/src/Client/HashTrait.php b/src/Client/HashTrait.php
index 79c9ca7..4a366ff 100644
--- a/src/Client/HashTrait.php
+++ b/src/Client/HashTrait.php
@@ -28,7 +28,7 @@ protected function hash(string $url, string $apiId, array $headers) : string
             }
         }
 
-        return sha1($apiId . $headerString . $url);
+        return $apiId . '.' . sha1($headerString . $url);
     }
 
     /**