What is the maximum limit of users for single topic subscription in Firebase?

Question

I am using Firebase topics to send notification.While doing so i came across the Firebase notification console which shows (topic-name)<1000 estimated user o

Answer 1

I can't found the answer link for you.But at 2015 GCM limit 1 million user to single topic subscription but which they already remove this limitation. FCM is using GCM as it core so which mean it is unlimited for user subscription to any topic.

You might get some point form this link

We’re now happy to announce that we’re allowing unlimited free topics for your app. This means app developers can place an unlimited number of devices within each topic and create an unlimited number of topics.

By your second question that obviously told you that fcm estimated lesser than 1000 user subscribe to that topic. It's doesn't mean you cannot send to over 1000 device. You have misunderstading the meaning of < 1000 estimated users.