Incremental Auth for the GMAIL api

Question

Google sign-in allows incremental permissions. Can it be also be used to increment to the Gmail API?

Google Sign-in Incremental auth page: https://developers.google.com/identity/sign-in/web/incremental-auth

Gmail API auth page: https://developers.google.com/gmail/api/

Answer 1

Yes. Incremental auth allows auth scopes to be added to an already-logged-in user.

For example, to add permission to read a user's emails, the "https://www.googleapis.com/auth/gmail.readonly" will need to be additionally requested, as described in the doc.