What exactly is an API?

What exactly is an API?

An application programming interface (API) is a set of routines, protocols, and tools for building software applications. An API expresses a software component in terms of its operations, inputs, outputs, and underlying types. An API defines functionalities that are independent of their respective implementations, which allows definitions and implementations to vary without compromising each other. A good API makes it easier to develop a program by providing all the building blocks. APIs often come in the form of a library that includes specifications for routines, data structures, object classes, and variables. In other cases, notably SOAP and REST services, an API is simply a specification of remote calls exposed to the API consumers. An API specification can take many forms, including an International Standard, such as POSIX, vendor documentation, such as the Microsoft Windows API, or the libraries of a programming language, e.g., the Standard Template Library in C++ or the Java APIs. An API differs from an application binary interface (ABI) in that an API is source code-based while an ABI is a binary interface. For instance POSIX is an API, while the Linux Standard Base provides an ABI”. To speak plainly, an API is the messenger that runs and delivers your request to the provider you’re requesting it from, and then delivers the response back to you

 APIs are useful in the following cases:

• The data is changing quickly
• You want a small piece of a much larger set of data
• There is repeated computation involved

When we want to receive data from an API, we need to make a request. Requests are used all over the web. For instance, when you visited this blog post, your web browser made a request to the Data-quest web server, which responded with the content of this web page.