The back-end is written in PHP and works by having a domain pointed to this service’s web-server IP address, with TXT records setup on the domain which tell the service which URL to used as the redirect destination.

The site uses PHP’s dns_get_record function and looks for the DNS_TXT values for the supplied domain. It loops through the values, then finds the value for the key which begins with redirect_, you can read the setup instructions on this projects page here.

The service is completely transparent to the end user, with only a few milliseconds of time spent on the redirect process.

You can view more about this project on GitHub here.