Clearing the API Air

There has been a lot of talk regarding web site API's recently. Whether it revolves around the hand to hand combat that LinkedIn and Facebook are about to engage in or the ever present beat of the Googleplex with their mapplets API, the API is the cool kid in school. API is a serious kid though: a cornerstone of emerging web technology, driving mash-ups, wadgets, and generally connecting the dots between walled gardens. Lost in this talk though, dare I say hype, is what an API actually is. There are two parts of the prevalent API usage that are actually quite different.

Ye Olde Screen Scraper
The original web application API is the screen scraper. If you saw something on an application page that you wanted you could write a client to access that page, grab the specific piece of information you were after, and then use it. This has been used for everything from short term dynamically generated pages to long term storage in a database to enterprise integrations. There are many reasons *not* to screen scrape such as changing HTML and licensing, but it is a simple, powerful, and time honored way of accessing data and processes.

The REST style API changed everything...well, sort of. What a REST API offers is often the same data and process access capability via an authorized interface. The data access typically goes far beyond what is presented on a page and processes are much more convenient to kickoff. There are concrete methods, data structures, and security. From a high level though not a lot has changed. We have essentially had the ability to pull information from other web applications since the first HTML page was presented. As Yoda, I am certain, once said "An open API an IPO does not make."

Along Came the Plug-in... and Facebook
Now mixed in to this API discussion are another set of API's. Rather than let developers pull data or kick off processes, plug-in API's allow developers to embed their functionality into in existing application... as if their functionality was native to that application. This changes the game. And that is what Facebook has done to much publicity recently, but the plug-in has been around longer than the web page. It is great that they have finally become friends although it is not an easy friendship. API's are challenging to get just right, plug-in API's are even harder. Not to mention standards.

An API that includes a plug-in component enables developers to not only build integrations, but to extend applications in a direction they deem worthy. Take a look at all of the widget platforms. They are essentially dedicated plug-in architectures. Together they have generated thousands of small applications.

So the next time someone says they are going to offer an API, ask them what kind. You'll be able to tell if they are just trying to get one more man on the moon or looking to orbit a distant star. And we should all be wary of any promises 9 months out, that's just long enough to forget.