Creating a session/user around an external data (coming via API trigger)

Hi,

I am getting some data to my system through an API. Once I have the data, how do I handle it to pass onto laravel so that it creates a user/session and avail my laravel coding functions? Currently, since I don't know how to invoke laravel without user physically logging it, I am replicating all PHP libraries to handle it external to laravel (which is what I need to improve).

Thanks, Saad