What is an API and why are they important to developers?

API route adds a new employee to the collection and returns it as JSON. © Mandeep Kaur

Ever wonder how we can play Spotify from within an Uber app? APIs enable two distanced entities to talk to each other in a standardized format.

Last week at Georgia Tech Coding Boot Camp, I learned about APIs and how they affect the way we use the internet. I was thrilled to write my own API for specific access into my own data by using the API development environment called Postman.

So what is an API?

API stands for Application Programming Interface, a software-to-software interface that enables two applications to exchange data among each other. Each time we use an app like Facebook, send an instant message, or check the weather on our phone, we’re using an API.

Simply put, when we use an application on our mobile phone, the application connects to the Internet and sends data to a server. The server then retrieves that data, interprets it, performs the necessary actions and sends us the information we wanted in a readable way — all of this happens via API.

Josh Walker, an analyst at Forrester Research, describes building an application with no APIs as “basically like building a house with no doors. The API for all computing purposes is how you open the blinds and the doors and exchange information.”

Why are APIs important?

APIs can be a service for developers. Every time developers write a new program, they don’t have to start from scratch to build a core application that tries to do everything. Instead, they can contract out certain responsibilities by using already created pieces that do the job better.

To explain this better, let me give an example.

Lego Blocks

Legoland Florida. © Mandeep Kaur

Who doesn’t love Legos? Lego bricks have a universal way of connecting to each other through small bumps and holes, which can be considered an API. It provides a simple and structured way to allow pieces to be built together in different ways. Similarly, software can connect together through APIs to create new and interesting mashups.

There is an API for just about anything we can think of. According to the Programmable Web, there are more than 20,000 published APIs — well over twice as many than there were four years ago. Beyond these publicly-exposed APIs, the number of private APIs is estimated to be in the millions.

Thank you for reading.