Thousand of APIs Paint a Bright Future for the Web

ProgrammableWeb's stat for API protocols and data formats

Once a novel idea that seemed limited to Flickr, the web-based API is now everywhere you turn — Twitter, Foursquare, Google Maps and thousands of other sites offer up their data in the form of an API.

APIs mean that third-party developers can build their own tools and mashups, which in turn helps to fuel the popularity of the web service. It’s hard to imagine where sites like Flickr and Twitter would be today without APIs.

In fact, these days some web services don’t even bother launching websites to go with their APIs — the API is the service. The SimpleGeo API, for example, doesn’t really have a corresponding website, it’s just an API that can be used anywhere, including inside mobile apps.

And APIs aren’t just something for external developers anymore. Increasingly web services are building their own sites and tools around their APIs — after all, why bother with an API if you aren’t going to use it yourself? Twitter is a good example of the “eat your own dog food” approach to APIs; Twitter’s website and its mobile clients are both developed off the same Twitter API that outside developers can tap into.

Former Webmonkey writer Adam DuVander, now Executive Editor at ProgrammableWeb, recently announced that ProgrammableWeb, an API tracking site, now lists some 3000 web-based APIs. To go along with that milestone DuVander breaks down some of the trends in today’s APIs.

It will come as no surprise to those actively developing or using APIs, but the overwhelming trend in APIs is moving toward serving JSON data over a REST interface. As DuVander notes in his post, how many “REST APIs” are truly RESTful is debatable, but certainly SOAP is on its way out and HTTP coupled with OAuth is the future.

When it comes to the data APIs serve up, XML is still the most used format, but JSON is hot on its heels and growing much faster. Even though there are still more XML APIs, the more recent the API, the more likely it’s serving JSON. In many cases — like Twitter’s streaming API and Foursquare’s updated API — companies are rapidly moving from XML to JSON.

The biggest thing that sticks out from ProgrammableWeb’s API trends is that the API, once a sort of “hey, that’s cool” option for progressive websites, is now a first class citizen of the web. Perhaps eventually something better than the REST/OAuth/JSON combo will come along, but the the API and the idea behind it — making data available to the entire web — isn’t going anywhere.