API

This term is an acronym for Application Programming Interface and is almost always used in technical, software development, and business contexts. It describes the bridge that allows two distinct pieces of software to talk to one another without needing to know the internal details of how the other is built.

In professional discourse, it is common to refer to the "endpoint" or "documentation" of an API. While it is a countable noun, it is frequently used as a modifier in compound nouns, such as "API key" or "API call," to describe the specific mechanisms used to interact with the interface.