What is an API?

Many people ask themselves, “What is an API?” API is the acronym for Application Programming Interface, which is a software intermediary that allows two applications to talk to each other. Each time you use the Facebook app, send an instant message, or check the weather on your phone, you’re using an API.

When you use one of these applications, the application on your phone connects to the Internet and sending data to a server. The server then retrieves that data, interprets it, performs the necessary actions and sends it back to your phone. The application then interprets that data and presents you with the information you wanted in a readable way. This is what an API is - this all happens via API.

What an API also does is provide 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. Instead, each communicates with small packets of data, sharing only that which is necessary—kind of 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.

APIs have become so valuable that they comprise a large part of many business’ revenue. Major companies like Google, eBay, Salesforce.com, Amazon, and Expedia are just a few of the companies that make money from their APIs. What the “API economy” refers to is this marketplace of APIs.

To learn more about APIs and how to design a great API, download the eBook Undisturbed REST: A Guide to Designing the Perfect API.

Next, learn why picking the right type of API for your project is so important. 

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