I would like to add the multiplayer functionality to my Android game. In particular it must be turn-based. I don't want to reinvent the wheel, so i need a framework/API or whatever that avoid to write the server side. It is just a personal project of mine, so i have not special requirements. Now, i know 3 possibilities:
I would like to know if there are other technologies or if any of the ones that i've written above is good.
https://developers.google.com/games/services/android/turnbasedMultiplayer
As someone said in comments, Google Play services is cross-platform and will work for iOS if you ported it in that direction. Also, the support in the way of tutorials and documentation is very great for this.
On top of that, you can integrate other Google goodies like high scores, badges, etc.