Andy Brudtkuhl wrote a tutorial on how to build a referral system in Laravel 5.

laravel referral

I recently launched a small product for Amazon Affiliates built with Laravel. At the heart of the application is a referral system. Users get bonus credits when they refer another user while getting recurring credit every time their referral uses the site. To tackle this the Laravel way, I got to use Requests, Middleware, and Cookies. I also integrated Google login using Socialite but that’s another post entirely.