How to notify users in the game?

Question

Android

Good afternoon, there is a multi-user toy application with the following principle:
1. The user performs an action
2. The user sends information about this action to the server
3. The server sends information to all players in the game
How can I implement the third step, in addition to Google Cloud Messaging and tapping the server on timeout?
At the moment I use Google Cloud Messaging, but it slows down a lot.

Answer 1

web sockets