oauth - Does the User ID returned by https://www.googleapis.com/oauth2/v2/userinfo changes over time -

We want to use the returned user ID as a unique identifier in an application.

Does it change the user id over time? For example, if the email address changes (Google Apps for Business)

User ID is a stateless identifier It is not affected by the change of email address, so it should be used as a key (no email address).