What is an API?

API stands for application programming interface. An API is a program that enables one software application to interact with another. In simple terms, an API is a messenger that takes requests and tells a system what you want it to do — and then returns the system’s response back to you.

An example of API use most people would be familiar with would be booking an airline flight on a flight prices comparison website like Expedia. Once you have input your desired departure and destination city, the dates you want to travel and the number of passengers, the comparison site searches through all available airline databases and serves you the options. This is done using APIs provided by each airline.

The same thing occurs when you type your information into a Hotel comparison site like Hotels Combined or Trivago. The platform requests and serves room rate information from every possible hotel database through their respective APIs.