Another word for API is “Application Programming Interface”, which is a software intermediary that allows two applications to connect to each other. Each time you use an app like Facebook, send an instant message or check the weather on your phone, you’re using an API.

What exactly is the meaning of an API? Finally learn for yourself in this helpful article from Mule Soft, the API experts.

What is an API?

When you use an application on your mobile phone, the application connects to the Internet and sends data to a server. Then the server retrieves that data and sends it back to your phone immediately. Finally, the application will interpret data and present the information you requested in a readable way. This process is called API - the flow of data happens via API.

To explain this better, let’s go through a familiar example. Imagine you’re sitting at a table in a restaurant and order your meals after reading the menu. The kitchen is part of the “system” that will prepare your order. What is missing here is the critical link to communicate your order to the kitchen and deliver food back to your table. This is where the waiter (or API) comes in. The waiter is the messenger - or API - that takes your order and tells the kitchen what to do. Then the waiter delivers the response back to you; in this case, it is the food.

Here is another real-life example similarity to API:

You may be familiar with the process of searching for flight tickets online. In order to book your flight, you interact with the airline’s website to access their database and see if any seats are available and how much the costs might be. Just like the restaurant, you have a variety of options to choose from, including destinations, luggage, dates, and more.

What if you are not using the airline’s website, but instead using available travel services such as Kayak, Expedia, or Agoda, which also aggregates information from a number of airline databases? The travel service, in this case, interacts with the airline’s API. The API is acted like your helpful waiter, to get information from the airline’s database to book seats, baggage options, etc. The API takes the airline’s response and delivers it right back to the online travel service, then shows you the most updated, relevant information.

The Modern API

Over the years, API has often described any sort of generic connectivity interface to an application. Even so, the modern API has taken on some characteristics that make them extraordinarily valuable and useful:

Modern API is adhered to standards (typically HTTP and REST), that are developer-friendly, easily accessible, and understood broadly.

They are treated more like products than code. They are designed for consumption for specific audiences (e.g., mobile developers), they are documented, and they are versioned in a way that users can have certain expectations of its maintenance and lifecycle.

Because of standardized factors, API has a much stronger discipline for security and governance, as well as monitored and managed for performance and scale

As any other piece of productized software, the modern API has its own software development lifecycle (SDLC) of designing, testing, building, managing, and versioning. Also, modern APIs are well documented for consumption and versioning.

API provides a layer of security

Your phone’s data is never fully exposed to the server, and likewise, the server is never fully exposed to your phone. Alternately, each communication is done with small packets of data, sharing only which is necessary - like ordering takeout. You tell the restaurant what you would like to eat, they tell you what they need in return and then, in the end, you get your meal.

Recently, API software has become so valuable that they comprise a large part of many business’ revenues. Google, eBay, Salesforce, Amazon, and Expedia are just a few of the enterprises that make money from their APIs. What the “API economy” refers to is this marketplace of APIs.

Source: Mule Soft