Adrian spoke about API’s at the last symposium and having no real understanding of what this meant… i did a little digging.

It stands for:

A – application

P – programming

I – interface

Well that sill means nothing to me… sorry Wikipedia, that just won’t do.

It went on to say, “specifies a software component in terms of its operations, their inputs and outputs and underlining types. Its main purpose is to define a set of functionalities that are independent of their respective implementation, allowing both definition and implementation to vary without compromising each other.”

Right….

In layman’s terms I think it means an API is a series of functions that programs can use to make the operating system work. Even simpler, an API lets you know how to make commands to tell programs or the computer how to do stuff.

I found an this excellent explanation below by Andy Cheung on Quora that helped me to understand API’s.

“Imagine you’ve got a black box with a big red button on top. When you press the button, the black box lights up.

In this example, pressing the red button means the black box will light up.  There is an understanding between you and the box that says “if I press the button, the box will light up.”

Think of an interface as the understanding between you and the box.  Now let’s extend the metaphor:

Instead of your finger, you’ve got a computer with – you guessed it – a mechanical finger.  You can tell the computer to press the button, and the box will light up.  See how this is still functionally the same? You told a computer to do your bidding, instead of your finger.

Let’s extend even further: instead of hitting a mechanical button, let’s pretend that you have to say “Light Up!” to the box in order to light it up.  If you could program your computer to say this, the black box will light up.  Still functionally the same thing.

Now imagine instead of saying this verbally, you write it out as a written command for the box.  And – this part is the most critical – the black box tellsyou the exact wording to use: lightMeUp().  The box also has an instruction manual on how to submit this command to the box.”