Currently, there aren’t any tools to grab all of the publisher-provided shorter URL in a standards-agnostic way. Tools that will grab either rev=”canonical” or rel=”shorturl”, but not both.

That’s where isshort.com comes in. isshort doesn’t care what URL shortening standard the publisher uses, it will find them all. This user-focused design will hopefully spur more sites and apps to provide their own short URLs.

...

Currently, isshort.com supports short URLs using the rel=”canonical”, rel=”shortlink”, and rel=”shorturl” standards.

Also, isshort shortens Amazon.com (amzn.com), YouTube (youtu.be), and NPR (n.pr) links.