diff --git a/README.md b/README.md
index 67f252b..99ddc3b 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,8 @@ make
 
 Except if you provide the argument `--youtube-operational-api-instance-url https://yt.lemnoslife.com`, you have [to host your own instance of the YouTube operational API](https://github.com/Benjamin-Loison/YouTube-operational-API/#install-your-own-instance-of-the-api).
 
+Except if you provide the argument `--no-keys`, you have to provide at least one [YouTube Data API v3 key](https://developers.google.com/youtube/v3/getting-started) in `keys.txt`.
+
 ```sh
 ./youtubeCaptionsSearchEngine
 ```