What is an API?

APIs are a hot commodity in web developed services these days. But for the lay person just getting their feet wet on the web, what is it?

API stands for "application programming interface," and despite the long, wordy name, APIs on the web are actually designed to do something, very, very simple: to allow programmers from outside web systems to access an existing website's services.

Take, for example, Twitter. Twitter has an open API which allows web developers from all over the internet to create ways to post messages to the Twitter social network. Programmers and web developers of independent blogs, news sites, commerce sites, or whatever-you-will can use the Twitter API to develop just about anything you can think of for Twitter posting. Like sharing videos, sending photos, tracking retweets, and so on. These applications are able to do what they do because they connect back to Twitter through the Twitter API.

Other famous examples of APIs include Google Maps (embed it on your website and add your own customizations to is data), Facebook, Amazon.com, and eBay. Add a few in the right places, and you can add a LOT to your website in terms of its services and value.

But with all of this positive upside to APIs, is there any hidden catch? Well, sort-of. APIs are ultimately dependent upon the service they were built on. So, if Twitter or Facebook were to ever suddenly go out of business, for instance, you would be left high and dry with useless APIs that did nothing whatsoever. It seems highly likely that any of that would be happening soon, however, so happy programming, and go get yourself an API today!