An application programming interface (API) is a set of tools, definitions, and protocols for integrating application software and services. It’s the stuff that lets your products and services communicate with other products and services without having to constantly build new connectivity infrastructure. APIs can be private (for internal use only), partnered (shared with specific partners to provide additional revenue streams), or public (allowing third parties to develop apps that interact with your API to foster innovation). Choosing to share your APIs has several benefits, including: