diff --git a/formats/JsonFormat.php b/formats/JsonFormat.php
index 400f91f..e765ef5 100644
--- a/formats/JsonFormat.php
+++ b/formats/JsonFormat.php
@@ -11,7 +11,7 @@ class JsonFormat extends FormatAbstract{
         // FIXME : sometime content can be null, transform to empty string
         $datas = $this->getDatas();
 
-        return json_encode($datas);
+        return json_encode($datas, JSON_PRETTY_PRINT);
     }
 
     public function display(){
@@ -21,4 +21,4 @@ class JsonFormat extends FormatAbstract{
 
         return parent::display();
     }
-}
\ No newline at end of file
+}