Your program/script sends a standard HTTP GET request, with the original (long) URL as a query argument. In response, it receives either a brand-new shortened URL, or an error message explaining what went wrong.

Sample - requesting a shortened URL for “http://www.youtube.com/”:

 •  http://surl.me/api-create.php?url=http%3A%2F%2Fwww.youtube.com%2F

Response:

 • http://surl.me/7gwe