How should backend server and android client communicate?

Question

Android

When registering a user, the android client receives information from this client's account and idtoken, should this token be sent with each client request to the server, or only once at the beginning?

Answer 1

You need to authorize once, then a token (or cookie) is issued for a certain limited time, which can be automatically extended without re-authorization.
But, if you make persistent cookies, then it is necessary in the application to allow the user to control their authorizations and reject left devices / browsers / half clients if the user observes unhealthy activity ..