What is Application Programming Interface (API) ?

An API or application programming interface is a piece of computer software that receives data from a user, usually performs some kind of processing of that data, then gives the user back some other data. Most of your interactions with applications and websites involve the use of an API. For example, when you search YouTube for a video, this search data is sent to the Youtube API, the API performs some matching algorithm on your search, then returns data in the form of videos that best match your search.

More formally, an API is a set of definitions, communication protocols and tools that enable developers to build applications that use information from other sources.

The data sharing in open banking is facilitated by open banking APIs.