Not with Firebase. Firebase uses GCM (Android) and APN (iOS) to send the notifications.
Ok thanx, and what would you use for such a task?
Edit: i would like to use my RPi2 as a server where 1 phone send a string to it and the RPi2 sends that string to another phone. Like this i could make simple multiplayer games that runs over the net.
The RPi2 will send the string via firebase my problem is only how to recive the string from phone app to RP2??
I was thinking of using mysql and php. So phone upload the string to mysql db and RP2 download it from that db and send to 2nd phone but i think it would be to slow...