How to get OAuth access to GMail?

Question

How can you get user-initiated access to read their email? It seems there is OpenID, OAuth, OAuth2 and random other solutions.

The best I came up with so far is OAut

Answer 1

The GMail API documentation says there is only one scope giving access to everything.

There is also a feature called GMail Inbox Feed which could be what you want, but it is only available on Google Apps domains.