I am trying to convert the login api using mail and password to login api using mobile number and otp. And I couldn’t understand the workflow of the flutter apps using api as a backend(php- laravel).

In my app, all the functionalities were working under API call including Authentication like Login api and Register api calls. But for some reasons, I wish change the flow of authentication through Firebase firestore and i need to store it in firestore database including OTP validation through Mobile Number.