diff --git a/config/api.php b/config/api.php
index 5720e57..f95333e 100644
--- a/config/api.php
+++ b/config/api.php
@@ -227,6 +227,7 @@
             'indent_size' => env('API_JSON_FORMAT_INDENT_SIZE', 2),
         ],
         'caseType' => env('API_CASE_TYPE', 'camel-case'),
+        'transform_keys_levels' => env('API_TRANSFORM_KEYS_LEVELS', null),
     ],
 
 ];