How many topics can we make in Firebase Cloud Messaging?

Question

I'm building an app where I am using Firebase Cloud Messaging. But I have some doubts. I want to know how many topics we could make in one app instance?

In official docs it writes that

when a single app instance subscribes to an excessive number of topics

it retrieves error TOO_MANY_TOPICS.

I want to know how many topics is allowed. I know that we don't have constraints about number of subscribers and that is okay, but I want to know how many topics could we make in one app instance. Appreciate any help.

Answer 1

There is no hard limit on the number of topics an instance can subscribe to, this limit, like many other limits on FCM are in place to prevent abuse. You are unlikely to hit the limit if an instance is subscribed to less than a few thousand topics. If however this is insufficient and you are indeed hitting the subscription limit then I'd advise that you contact Firebase Support.

Answer 2

Here, One app instance can be subscribed to no more than 2000 topics.