Google Cloud Messaging(GCM) for Android

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, and also to receive messages from devices on the same connection. 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.

You might have heard of C2DM (Cloud-to-Device Messaging), which basically allowed third-party applications to send (push) lightweight messages to their Android applications. Well, C2DM as such is now deprecated and replaced with its successor up the evolutionary ladder: GCM, or Google Cloud Messaging.

Key Features = 

• Send data from your server to users' Android-powered devices
• Send "send-to-sync" messages
• Send messages with payload
• Faster, easier GCM setup
• Upstream messaging over XMPP
• Seamless multi-device messaging
• Get Started

The set-up process will provide you with the two most essential pieces of information needed to run GCM:

1. An API key, needed by your server to send GCM push notifications
2. A Sender ID, needed by your clients to receive GCM messages from the server