Google Cloud Messaging
Firebase Cloud Messaging (FCM) is the new version of GCM. It inherits the reliable and scalable GCM infrastructure, plus new features! See the FAQ to learn more. If you are integrating messaging in a new app, start with FCM. GCM users are strongly recommended to upgrade to FCM, in order to benefit from new FCM features today and in the future.
Engage your users across Android, iOS and Chrome
Send data from your server to your users’ devices, and receive messages from devices on the same connection. The GCM service handles all aspects of queueing of messages and delivery to client applications running on target devices, and it is completely free.
Versatile Messaging Targets
Distribute messages to your client app in any of three ways to single devices, to groups of devices, or to devices subscribed to topics.
For purposes such as alerting users, chat messaging or kicking off background processing before the user opens the client app, GCM provides a reliable and battery-efficient connection between your server and devices.
Send acknowledgments, chats, and other messages from devices back to your server over GCM’s reliable and battery-efficient connection channel.
Send messages from the cloud
Send a message using GCM HTTP connection server protocol:
Handle a downstream message on an Android device: