If you see this page, there is a good chance something has gone wrong. Try your link again!
It should have this format:
If this is the page you are looking for:
You can find the code for this project on Github.
There also is an API available in /api/.
You can use any plugin from the list below by adding it to the end of the link.
qr: Make a nice QR code from the short link.
Use GET parameter 'size' and 'margin' to set the image size & margin.