APIs (application programming interfaces) define how developers can programmatically interact with an external application. Software developer, Kevin Bowersox, outlines the basics of APIs including: the purpose of an API, important API concepts such as interfaces, real world application of APIs, and how developers can leverage APIs to build applications more quickly.

Dive deeper into APIs with our Designing Web APIs Learning Path. With the growing use of mobile devices, software-as-a-service, and the Internet of Things, APIs have become a critical part of a company's digital strategy, allowing businesses to share capabilities and data, build community, and foster innovation.

Article image: Screen from "What is an API?" (source: O'Reilly).