Send Notification Build and send notifications is very easy: Content content = new Content(ACTION_CHAT, // requestCode "Hi :)", // title "Welcome to notifications!", // body "my_room", // room "myChannel", // channel ID (Android 8) "Test channel", // channel description (Android 8) "https://lh6.google...oto.jpg", // small photo url "https://lh6.google...oto.jpg", // big photo url ); ArrayList<String> ids = new ArrayList<>(); // device ids that will receive // the notification ids.add("56783g345guik456"); // <-- device id A ids.add("48484aad18e02d76"); // <-- device id B // send Notifications.notify(Notifications.builder(content, ids)); Be careful sending notifications to yourself. Only should do for testing purposes. Content content = new Content(...); ArrayList<String> ids = new ArrayList<>(); ids.add(Rotor.id); // <-- don't do it in production environments Notifications.notify(Notifications.builder(content, ids));