diff --git a/INSTALLATION.md b/INSTALLATION.md
index de1ce564..60087c83 100644
--- a/INSTALLATION.md
+++ b/INSTALLATION.md
@@ -38,6 +38,7 @@
 ## API keys
 
 * Get a Google OAuth 2.0 client key & secret from [console.developers.google.com](https://console.developers.google.com)
+* Add `https://beta.notify.moe/auth/google/callback` as an authorized redirect URI
 * Create the file `notify.moe/security/api-keys.json`:
 
 ```json