How to check the delivery status of a message and whether it is read or not in cloud messaging android studio Firebase? I send messages, they come, but I do not know how to check whether the message has been read or not.
There is no API to track delivery status for individual messages in Firebase Cloud Messaging. If you need to know whether a user has received (or seen) a message, you should implement that in your own application logic.
One example of this is to only send data messages (that are not automatically displayed by the system), handle the display of a notification for those messages yourself, track whether the user interacted with the notification, and then store that information in a cloud-hosted database.