Uses of APIs

API is the acronym for ‘Application Programing Interface’. It acts as a software intermediary among applications and lets them communicate with each other. Whenever a person sees a weather forecast, sends a text via Facebook, and buys a ticket online, the person uses API. API exists everywhere. As far as usage is concerned, API is widely used in different aspects of life.

Operating system and APIs

API specifies the interface between an application and the operating system. For instance, the Portable Operating System Interface (POSIX) is a set of standards established by the IEEE Computer Society for ensuring interoperability across operating systems. POSIX plays a role by defining standard APIs that allow the operating system and POSIX to communicate. Linux is one such implementation of the POSIX APIs in an operating system.

Remote APIs

Remote APIs help developers in manipulating remote resources through standard protocols and standard communication with no regard for language or platform. For instance, with the same functions, Java database connectivity API allows developers to tackle umpteen databases. Whereas, java remote method invocation API is used to invoke functions that operate remotely but appear local to the developer.

Consequently, the object that appears on the screen is modified as local by applying the process of remote method invocation APIs. Therefore, remote APIs are significant in modifying proxy objects.

Web APIs

Web APIs are defined interfaces. Web APIs are used for interactions between an enterprise and an application. It further specifies a function, its domain, functional provider and exposes the path for its API users. This approach is called an architectural approach that simultaneously revolves around different services provided to different customers.

Whenever it is used in the context of web development, an API generates certain specifications such as HTTP (Hypertext Transfer Protocol) request messages, a structure of response messages in the format of XML (Extensible Markup Language), and JSON (JavaScript Object Notation).

For example, a shipping company API helps users access services and rates without involving developers to provide rates separately to every user. Web APIs also allow mashup. Mashup is a combination of various applications. In social media, APIs allow content sharing. Thus, content can be generated, shared, and posted on different platforms on the web.

Libraries and frameworks

The interface of library software is one of the tasks of API. An API interprets and explains the expected behavior, while a library is classified as the actual implementation of rules. Single API can have various implementations in the form of different libraries that share the same programming interfaces.

API use can vary depending upon the language of a program. An API for procedural language consists of basic routines to execute codes, manipulate data, or handle errors. Contrary to the above, an API for an object-oriented language would provide a specification of classes and class methods.

An API is also employed for software frameworks. A framework might be based on several libraries implementing different APIs. However, unlike the typical APIs, the control in software frameworks is mediated by the third party. The control can go to the framework’s hand by the method of inversion of control.

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