Firebase send notification to specific user

Send messages to any device Firebase Cloud Messaging (FCM) provides a reliable and battery-efficient connection between your server and devices that allows you to deliver and receive messages and notifications on iOS, Android, and the web at no cost .

The Firebase console provides analytics-based A/B testing to help refine and improve marketing messages . After you have developed logic in your app to receive messages, you can allow non-technical users to send messages per the instructions in the Notifications page in the Firebase Help Center.

You can send SMS Verification using Firebase and you cannot send ordinary SMS through Firebase. You can send using Twilio instead.5 Haz 2017