How to send Device to device notification by using FCM without using XMPP or any other script.?

Question

Is there any way to send Upstream notification message through FCM from one android device to another devices connected with Firebase database.

I kn

Answer 1

Finally, after 2 months of trying to maintain reliable server script myself, I suddenly found OneSignal. It's completely free, supports device-to-device push messages on iOS, Android, WP and browsers.

Hope, I won't get flag for promotion spam, but it's currently the only (and easiest) way to be completely "backendless".

Also, it's completely secure way. Nobody can send push unless he knows special OS user id, which you can store in Firebase Database protected by rules.

UPD: It's not a replacement for Firebase. It has only push service and nothing else

UPD2: Firebase now has Functions, and examples of it usage has sending FCM. You now don't need any other server or service. Read more in official samples https://github.com/firebase/functions-samples