Is Google account neccessary for Google Play Game Services?

Question

I want to use Google Play Game Services to implement multiplayer in my game. The game will be deployed on Android and iOS.

Is it neccesary for iOS user to have an Google account in order to use GPGS ?

Answer 1

For the users using your game, They must sign in with a Google account to use multiplayer so that Google could generate an ID of the user to store in the db for achievement or for game search.

And if they do like to play with a friend, the friend must be in their circles.

Answer 2

yes, I believe that the user needs to have a Google account. When you go to the Developer Console to register the game ( https://play.google.com/apps/publish/signup/ ), you get prompted for signin via Google.