API (Application Programming Interface)

What is an API (Application Programming Interface)?

API (Application Programming Interface) is a specific set of standardized program code requests software programs use to communicate among themselves. They are necessary for information exchange. Applications depend on operating system APIs to perform basic functions (i.e.: file system access). The program’s API determines how a developer must request services from that program. Although (middleware) they are quick and easy, independent software vendors may find them constraining. APIs prevents future developers from having to find or review the source code. To be effective APIs must be understandable to future developers. However, companies may routinely perform “API churn” (changing APIs to avoid them being cloned). For example, Windows architecture allows the company to dump new APIs rather than hide them.