Using APIs

An API (Application Programming Interface) is a set of commands, functions, and protocols which programmers can use when interacting with a specific system. An API allows programmers to use predefined functions to interact with the system, instead of writing them from scratch. It specifies how software components should behave and often is used when programming graphical user interface (GUI) components.  A good API makes it easier to develop a application by encapsulating business rules and providing functional building blocks.