Firestore Send Email Extention - Google Sign in with App Passwords guide

[yamankatby]

[READ] Step 1: Are you in the right place?

Issues filed here should be about a feature request for a specific extension in this repository. To file a feature request that affects multiple extensions or the Firebase Extensions platform, please reach out to Firebase support directly.

[REQUIRED] Step 2: Extension name

This feature request is for extension: firestore-send-email

What feature would you like to see?

Add a guide describing how to configure the extension to authenticate with a Google account using Sign in with App Passwords

How would you use it?

Since Google dropped less secure apps authentication for third-party apps, a step-by-step guide can be added to the README or somewhere in the docs.