| FirebaseMessaging | Firebase Cloud Messaging enables apps to communicate with their app servers using simple messages. |
| FirebaseMessagingService | Base class for communicating with Firebase Messaging. |
| RemoteMessage | A remote Firebase Message. |
| RemoteMessage.Builder | Builder object for constructing RemoteMessage instances. |
| RemoteMessage.Notification | Remote Firebase notification details. |
| SendException | Firebase message send exception. |