Application programming interface key

An application programming interface key (API key) is a code passed in by computer programs calling an application programming interface (API) to identify the calling program, its developer, or its user to the Web site. API keys are used to track and control how the API is being used, for example to prevent malicious use or abuse of the API (as defined perhaps by terms of service).

The API key often acts as both a unique identifier and a secret token for authentication, and will generally have a set of access rights on the API associated with it.

API keys can be based on the universally unique identifier (UUID) system to ensure they will be unique to each user.