API’s are the new doors into software programmes and web sites that allow other software programmes to “talk” to them without human interaction.
If you imagine the software as a big building, then the front entrance would be the “user interface” (where we all use the software i.e. when we browse the web), then the “application interface” is like the delivery entrance, where deliveries are sent. It’s another door to the same building but for a different type of building user. In this case its a door made for other computers instead of people.
An Application Programming Interface (API) allows other software applications to put information in, get information out and use services as if they were real users. For example the Google Maps API allows other applications to send a list of longitude and latitude coordinates and it will return a map with markers on each of those coordinates. Check out this Google Map ‘mash-up’ of World Bank country data to see what APIs can make easy.
APIs are not all created equal – some are wonderful and some are downright difficult to use.
As a web 2 programmer I deal with APIs on a daily basis. In my next blog post I’ll explain some of the ways to evaluate whether an API is any good, before you decide to use it.