What are APIs and how do they work?

What is an API?

API stands for Application Programming Interface, a software that makes use of data, server software and other applications that acts as an intermediary between apps. In other words, an API allows applications to communicate with one another; just like a translator would make sure speakers of different languages understand each other.

APIs are go-betweens for the apps we find on our smartphones and tablets, they are highly versatile and can be found on web-based systems, operating systems as well as database systems and computer hardware.

Developers use APIs by reusing codes they would have developed prior, or source ready-made codes for a particular command. This recycling of codes makes developers jobs far easier and much more efficient to the process they’re looking to improve.

When developed correctly, a good API creates stable building blocks for developers to embellish and integrate with other apps. But how exactly do APIs and apps communicate with one another?

How does an API work?

Much like other forms of communication, APIs have sets of rules that need to be followed in order to communicate with computers, applications and even machines. An API can be considered a middleman between machines that need to communicate in order to achieve a specified task.

A great example of this is logging into a platform via web APIs. Let’s take Twitter as an example. Whenever you log in to Twitter from your smartphone, you are telling the application that you would like to access your account. The mobile app communicates with an API to effectively log you in with your correct credentials. Twitter would then gain the information off its servers and successfully transfer the data to the mobile application, granting you instant access to your Feed. A daily habit for most that needs to jump through quite a few hoops.

APIs can be used for communication between a myriad of machines and have been around for quite some time. It was only up until recently that APIs gained popularity, giving companies the edge over their competitors to speed up communication between platforms and machines for seamless connectivity.

What types of APIs are there?

While web APIs are some of the most common, there are quite a number of APIs on the market. Here are some of them:


REST stands for representational state transfer and delivery data that makes use of the lightweight JSON format. They are chosen by public APIs for their dependability and performance.


Simple Object Access Protocol (SOAP) is slightly more complex than REST and has been in use since the 1990s. It makes use of XML to transfer data. Its strict rules and top security requires much more bandwidth than REST.


This markup language is a protocol that uses XML format to transfer data in the same way SOAP does, but it is far older and communicates with an HTTP request that connects to a server to generate a response.


Similar to XML-RPC, JSON-RPC works in the exact same way apart from one protocol format. As the name suggests, JSON uses JSON instead of XML. This system software calls on a single method of a remote system.

A developer’s use of APIs facilitates the communication between the apps that we make use of on a daily basis. This means of contact is what keeps us browsing and scrolling through our Facebook feeds, Spotify playlists and other everyday apps.