Sending notification to multiple devices without using subscribeToTopic in firebase

Question

I know how to send notification to single user and multiple users by using subscribeToTopic ("all"), but how can I send Notification to a group of people according to my wish

Answer 1

To solve this, use Cloud Functions for sending notifications. You can send a notification to a single user or to a group of users according to your needs. I've exaplained the entire flow for doing this in my answer from this post. So a notification can be sent, even if the user has not opened the app. He will receive the notification every time something interesting happens.