koobas.hobune.stream
a global var
have any idea of how i can create a single var that will display on every instance of an app and each instance will be able to increment the value and view the total value. Imagine a game where each player has to make a donation in a box and each time a player add 1$ the box get incremented by 1$ and others will be able to check the total donation by all users.
What you need is pretty much a server / database / cloud.
It's a pretty broad question and it can be implemented in a hundred different ways, so I'll just leave these links here. There are tutorials and plenty of documentation about all of these so they should get you started. These are all services you can use to implement connectivity in your games in different ways: just storing data online or even doing real time multiplayer things.
https://developers.google.com/games/services/
