API stands for Application Programming Interface, which is a set of protocols, routines, and tools for building software applications. APIs allow different software applications to communicate with each other, enabling developers to create complex functionality more easily. In web development, APIs are used to extract and share data within and across organizations. There are two main types of APIs in web development:

• Browser APIs: These are built into web browsers and can expose data from the browser and surrounding computer environment. For example, the Web Audio API provides JavaScript constructs for manipulating audio in the browser.

• Third-party APIs: These are built into third-party platforms, such as Twitter or Facebook, and allow developers to use some of those platforms functionality in their own web pages.

APIs can be used to integrate new applications with existing software systems, increasing development speed because each functionality doesn’t have to be written from scratch. They can also be used for mashups, where information from one site can be mixed with that of another. APIs are designed for consumption for specific audiences and are documented and versioned in a way that enables users to have clear expectations of their maintenance and lifecycle.