Real-time API prefix for subscription

What is the maximum subscription count for the Instagram Live API ?

Talking about a server that processes custom users and registers them for a specific Instagram live API subscription.

For a large number of users, would this be viable?

During my search for some information on this, some people talked about 30 subscriptions maximum ... But nothing is official .

I just wanted to know more about this limit and if someone can point me to the official documentation pointing this out.

Thank you in advance!