This post is another Explainer post, and it’s about APIs and what they can do. Through a couple of examples, by the end of this post you should know what APIs are and how they are useful and why they are popping up in so many Web 2.0 applications.
I found this site a while back and it’s a really cool demonstration of what the power of Google Maps can do.

It’s called Goggles, and it’s essentially a Flash-powered ‘flight simulator’ where you can fly over real images of the world and explore Google Maps with a little bit more finesse.

(Linux users - it requires Flash 8, which isn’t on Linux, but I found a workaround if you want to try this and other Flash 8 stuff out).

It’s an impressive demonstration of what the Google Maps API can do and it’s certainly an interesting project. A lot of sites and web services have made use of the Google Maps API; for example, Frappr uses it for all the maps, but this is the most inventive and most complex use of the API I have seen yet.

Google opened the API up so that site developers could do this sort of thing with Google’s data and a lot of Web 2.0 services also have (slightly less impressive) APIs, for example, Youtube has one so that you can include some of their video services on your site.

So what exactly is an API? Find out after the jump.

API stands for application programming interface, and it has historically been used to describe the sets of developer’s tools in operating systems that make it easier for them to build applications for that operating system. From Wikipedia:

An application programming interface (API) is the interface that a computer system, library or application provides in order to allow requests for services to be made of it by other computer programs, and/or to allow data to be exchanged between them.

So in the context of web APIs, it’s an online application hosted by someone that allows other web applications to exchange data with it. For Google Maps, that means Goggles (as an example) can query the Maps API for images of a particular location in the world, and Maps responds by sending the appropriate images. From that, Goggles creates the flying experience and as you move around, it anticipates when you’ll want a new piece of terrain and makes another request to get those images.

This is a bit simplified, but the main concept is mostly there. In fact, conceptually it is quite simple. Something (the client we’ll call it) asks for something and something else (the server) responds with an answer.

The use of APIs such as Google Maps is what is driving some of the new web technologies we’re starting to see now. Smaller companies and services inevitably don’t have the time or money to implement solutions of the complexity of Google Maps, for example, but by the APIs being open, everyone can benefit. Google gets their name on a few extra sites, the sites get cool functionality without building it themselves and the users get a better experience.

Everyone’s happy.