diff --git a/config.json b/config.json
index 37a9118..3a81cf4 100644
--- a/config.json
+++ b/config.json
@@ -12,7 +12,8 @@
   "version": 3,
   "online_editor": {
     "indent_style": "space",
-    "indent_size": 4
+    "indent_size": 4,
+    "highlightjs_language": "arturo"
   },
   "test_runner": {
     "average_run_time": 10