Registering and authenticating users from external login API

Hello folks,

I'm kinda beginner in the "deeper" working method of Laravel, that is why I am asking this question here. Given a Laravel 5.7 application and an external login API that I want to authenticate the application from.

Upon login, the API shall be called with the following pattern: https://login.example.com/?url=https://laravelapp.com

If our domain is whitelisted for using the API, it redirects the URL https://laravelapp.com/?token=........, otherwise ...?token=error

With this token that API passed to us, we can retrieve the user data in JSON format by calling https://login.example.com/user.php?token=............

App shall use the login API every time when a user logs in, and upon first login we shall register a new user instance to "users" table with the data retrieved from the API.

Thank you in advance!

D