Firebase Cloud Functions - limit calls per second per IP

I am planing to create few API calls based on Firebase Cloud Functions and DB.

Every call will access to Firebase DB, get data or modify data in Firebase DB and return relevant responce.

But i am afraid of DDOS atacks, or similar massive access attacks.

By my usecase scenairio I am sure that user does not need more than 25 API calls in one minute.

Is it possible to set such limit to my Firebase Cloud Functions/DB ?

How can i protect my Firebase from overusing by unconscious individuals.