A Google Cloud Messaging (GCM) Android client is a client app that runs on an Android device. To write your client code, we recommend that you use the GoogleCloudMessaging API and Android Studio with Gradle. Here are the requirements for running a GCM Android client: 1  GCM requires devices running Android 2.2 or higher that also have the Google Play Store application installed, or an emulator running Android 2.2 with Google APIs.