diff --git a/src/Transport/HttpTransport.php b/src/Transport/HttpTransport.php
index 44da08d..599ff5a 100644
--- a/src/Transport/HttpTransport.php
+++ b/src/Transport/HttpTransport.php
@@ -193,7 +193,8 @@ public function read(array $queries, int $concurrency = 5) : array
                 $multipart = [
                     [
                         'name'     => 'query',
-                        'contents' => $query->getQuery().' FORMAT JSON',
+                        'contents' => $query->getQuery() . (strpos($query->getQuery(), ' FORMAT ') === FALSE ? ' FORMAT JSON' : ''),
+
                     ],
                 ];