Google cloud messaging - Developing Android Apps

“Performance Testing for Firebase Cloud Messaging Backend” by Zijian Yao (Firebase/Google)

Push Notification in Android Using GCM (Google Cloud Messaging)

Google Cloud Messaging

Android Push Notifications using Google Cloud Messaging (GCM), PHP and MySQL - Android Example

Google Cloud Messaging - Push Notifications - Demo

Google Firebase Cloud Messaging Step By Step Guide

Setup the Google Cloud Messaging Plugin for Android