Application programming interface (API)

An application programming interface (API) is a communication system that enables two applications or platforms to "talk" to each other. The APIs of social networks allow these platforms to integrate with other software providers and applications. For example, .simple uses Facebook's API to publish posts and Instagram's API to schedule posts.

When Instagram wanted to shut down the shady "growth hacking" apps that people were using to artificially grow their audience, they shut down the old API and introduced a new one with much stricter privacy controls.