Any Realtime app needs to send Realtime notifications. Firebase Cloud Messaging (FCM) provides a platform that helps you send the messages and notifications to the app user in Realtime. You can send hundreds of billions of messages per day for free across different platforms: Android, iOS, and web. We can also schedule the message delivery—immediately or in future. Notification messages are integrated with Firebase Analytics, so no coding is required to monitor user engagement.

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• Chrome: 50+
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• Opera Mobile: 37+

// Retrieve Firebase Messaging object.
const messaging = firebase.messaging();
messaging.requestPermission()
.then(function() {
 console.log('Notification permission granted.');
 // Retrieve the Instance ID token for use with FCM.
 // ...
})
.catch(function(err) {
 console.log('Unable to get permission to notify.', err);
});