Application Programming Interface (API)

An Application Programming Interface (API) is a set of programming code that enables data transmission between one software product and another. It also contains the terms of this data exchange.

APIs consist of two components:

1. a technical specification that describes the data exchange options between solutions with the specification done in the form of a request for processing and data delivery protocols and
2. software interface written to the specification that represents it.

APIs contain and are implemented by function calls – language statements that request software to perform particular actions and services (like retrieving specific data from the server).

Main API specifications or protocols are

• Remote Procedure Call (RPC),
• Service Object Access Protocol (SOAP),
• Representational State Transfer (REST),
• gRPC, and
• GraphQL.