Cloud Messaging

Firebase Cloud Messaging (FCM) is a messaging service that offers a cross-platform messaging solution. FCM can be used to notify when there is new data available to sync. Using FCM, we engage the user and increase the chance of user retention. FCM allows up to 4 KB of payload transfer. The legacy way to send messages and notifications was the now-deprecated GCM. Google officially recommends using FCM for notifications and data messages.

There are some outstanding key capabilities, such as versatile message targeting, which allows device-specific messaging and the grouping of devices, including those subscribed to topics, and the sending of messages from user apps that can send acknowledgments, chats, and other messages from FCM.

FCM essentially includes two components: sender and receiver. The sender can be the application backend server or trusted services such as Firebase functions. Receivers are mobile and web platforms such as iOS and Android devices. 

Messages can be fired...