An API (Application Programming Interface) is an interface that allows user programs to communicate with infrastructure programs (databases, communications software, file management, software packages etc.), without changing the "rules of language" and the messages and commands which the application uses to communicate with the infrastructure program. APIs are a means of "enriching" an infrastructure program and adapting it to organizational needs without modifying either the infrastructure program or the interface between it and the user.

• See also "Open Systems" in the Other Methods and Methodology Integration Kit

• See also Middleware and Workflow