diff --git a/config/config.yaml b/config/config.yaml
index b0264e908..555a4e24c 100644
--- a/config/config.yaml
+++ b/config/config.yaml
@@ -26,6 +26,7 @@ RPM: 10
 #GOOGLE_API_KEY: "YOUR_API_KEY"
 ## Visit https://programmablesearchengine.google.com/controlpanel/create to get id.
 #GOOGLE_CSE_ID: "YOUR_CSE_ID"
+## Visit https://serper.dev/ to get key.
 
 #### for TTS