A referral code is the magic part tacked on to URLs shared through the SDK that allows us to credit a user for inviting others. You do not need to create these yourself, but they might be useful if you want to identify specific users as seen by Megacool.
A referral code consists of two parts:
The userId is assigned from the server-side the first time the app gets online, but it's possible to create shares before this happens. These shares will be associated with a referral code that doesn't have a userId yet.