diff --git a/example/config.json b/example/config.json
index 4229b5e..83cfe98 100644
--- a/example/config.json
+++ b/example/config.json
@@ -2,6 +2,8 @@
 "client_id": "YOUR_CONSUMER_KEY",
 "client_secret": "YOUR_CONSUMER_SECRET",
 "redirect_uri": "https://a.callback.url",
+"__comment": "grant_type is only needed for Client Credentials Grant, otherwise can be removed",
+"grant_type": "client_credentials",
 "access_token": "access-token-if-known-otherwise-remove",
 "refresh_token": "access-token-if-known-otherwise-remove",
 "expires_at": "2018-01-01T01:00:00.000Z",