What is an API?

An API is a set of programming codes that enables data transmission between one software product and another. It also contains the terms of this data exchange.

Application programming interfaces consist of two components:

Technical specification describing the data exchange options between solutions with the specification done in the form of a request for processing and data delivery protocols Software interface is written to the specification that represents it The software that needs to access information (i.e..,X hotel room rates for certain dates) or functionality (i.e., a route from point A to point B on a map based on a user’s location) from another software, calls its API while specifying the requirements of how data/functionality must be provided. The other software returns data/functionality requested by the former application.

And the interface by which these two applications communicate is what the API specifies.

The Red Hat specialists note that APIs are sometimes considered contracts, where documentation is an agreement between the parties: “If party first sends a remote request structured a particular way, this is how the second party’s software will respond.” The API documentation is a manual for developers that includes all necessary information on how to work with the API and use the services it provides. We will talk more about the documentation in one of the next sections.

Each API contains and is implemented by function calls – language statements that request software to perform particular actions and services. Function calls are phrases composed of verbs and nouns, for example:

• Start or finish a session
• Get amenities for a single room type
• Restore or retrieve objects from a server.

Function calls are described in the API documentation.

APIs serve numerous purposes.Generally, they can simplify and speed up software development. Developers can add functionality (i.e., recommender engine, accommodation booking, image recognition, payment processing) from other providers to existing solutions or build new applications using services by third-party providers. In all these cases, specialists don’t have to deal with source code, trying to understand how the other solution works. They simply connect their software to another one. In other words, APIs serve as an abstraction layer between two systems, hiding the complexity and working details of the latter.