Laravel 5 authenticate users through external API

I'd like to know is it possible to extend the built-in authentication to use an external API to authenticate a user? I'm a Laravel newbie, so I'd appreciate your help. I'm making a custom app in Laravel 5.2 for my client, but I don't a direct access to their database server and I can only call their API to get users' details.

Thanks.

via Chebli Mohamed