On the Pineco.de site they've posted a tutorial for the Laravel users out there showing how to use the framework's "signed URL" functionality to create invite links for your application.

We can handle user invitations easily with the old and good database way. We create an invitation, store it with a unique token, then email it to the user. If the user uses the link, we can delete it from the database and that’s all. Now let’s give a try to Laravel’s signed URLs to handle a database-less solution.

The article starts by explaining what the "signed route" functionality is and how to generate then using the URL helper. It also shows how to use the "signed" middleware to validate the signature provided on the request. Finally, it shows how to configure, send and use the hashes to handle user registration.