Google Cloud Messaging for Android

Google Cloud Messaging for Android (GCM) is a service that allows you to send data from your server to your users' Android-powered device. This could be a lightweight message telling your app there is new data to be fetched from the server (for instance, a movie uploaded by a friend), or it could be a message containing up to 4kb of payload data (so apps like instant messaging can consume the message directly).

The GCM service handles all aspects of queueing of messages and delivery to the target Android application running on the target device. GCM is completely free no matter how big your messaging needs are, and there are no quotas.

To learn more about GCM, you can join the android-gcm group and read the following documents:

Getting Started
Read this document to learn the basic steps involved in developing Android applications based on GCM.
Architectural Overview
Read this document for a description of the underlying concepts and architecture in GCM.
Demo App Tutorial
Read this document to walk through setting up and running the GCM demo app.
Advanced Topics
Read this document to get a more in-depth understanding of key GCM features.
Migration
Read this document if you are a C2DM developer moving to GCM.
API Reference
Helper libraries for client and server development.