What is an API?

Product manager for Blogs.com and lead for their blogger training, Andy Wibbels, wrote an outstanding blog article, “What is an API?” As a programmer I know what an API is but I have a hard time explaining the concept to non-programmers. Now, Andy has done the explaining for me.

Andy’s article does a nice job of explaining without overwhelming, and his short introduction skillfully avoids going into more detail than most people want. If you’ve ever wanted to explain (or understand) the connection between mashups and APIs, or how Twitter’s massive and rapid success can be attributed to embracing APIs, then this is the article for you.

APIs and Web 2.0 are intimately related. Tim O’Reilly, the man who is credited with coining the term “Web 2.0,” describes Web 2.0 as “the design of systems that harness network effects to get better the more people use them.” (See this article for a reference to this quote.) It is the proliferation of APIs, which facilitates the mashing up of services, that powers Web 2.0 and allows the rich interaction that makes the services grow, evolve, and improve.

APIs are at the heart of a number of technologies I’ve blogged about. Here are a few examples:

1. “Query-free” federated search. The prototype software that helps writers to find relevant content and references by watching what they type uses APIs to identify the right search terms and to perform searches of resources.
2. In A new paradigm for federated search, venture capitalist Steve Jurvetson’s distributed search paradigm relies on APIs to provide information about what pages users are browsing and to retrieve relevance information from the “Collective” database populated by others.

3. Federated search and information in context tells about new features of the Science.gov 5.0 release of the federated search application: clustering, new content sources, mashup of Wikipedia and EurekAlert results. Each of those new features relies on an API in one way or another.

APIs are absolutely everywhere! Federated search relies heavily on the technology. Searching sources, especially those that don’t have to be screen-scraped, uses APIs to specify how to search and how to retrieve results. AJAX is based on an API that specifies how to partially update a web page. Many modern web applications, not just federated search tools, use AJAX. If we consider that APIs are nothing more than protocols that allow two programs to communicate, even your humble web browser uses an API to get to your favorite federated search applications by talking to web servers using a standard called HTTP.

Can you think of other places where APIs are used with federated search? Leave a comment and let us all know.

Tags: federated search