There are a few ways! For example when the user signs in, you could assign them a random chat room https://firebase.google.com/docs/functions/auth-events https:

There are a few ways! For example when the user signs in, you could assign them a random chat room https://firebase.google.com/docs/functions/auth-events https://firebase.google.com/docs/functions/auth-events lets you trigger on initial sign in. You can also hook up to regular HTTP triggers, and make it like an API call: https://firebase.google.com/docs/functions/http-events https://firebase.google.com/docs/functions/http-events