diff --git a/app/config/rest.yml b/app/config/rest.yml
index 3d0c0dd..3617857 100644
--- a/app/config/rest.yml
+++ b/app/config/rest.yml
@@ -6,9 +6,12 @@ fos_rest:
         serialize_null: true
     param_fetcher_listener: true
     body_listener: true
-    format_listener: true
+    format_listener:
+        rules:
+            - priorities: [json, xml]
+            - fallback_format: json
     view:
-        view_response_listener: true
+        view_response_listener: 'force'
         formats:
             xml: true
             json : true
diff --git a/app/config/routing.yml b/app/config/routing.yml
index 53af805..e538f35 100644
--- a/app/config/routing.yml
+++ b/app/config/routing.yml
@@ -10,6 +10,7 @@ api_book:
 api_category:
     resource: AppBundle\Controller\Api\CategoryController
     type: rest
+    defaults: {_format: json}
     prefix: api
 
 fos_js_routing: