What is API?
API stands for Application Programming Interface. It is a way for software applications to interact with each other. Thus API forms a connection between two or more applications; it works like a messenger that takes a request from an application, communicates and commands the system, and then returns the response of the system back to the application. For example, a travel service web application obtains data from the server through API.
However, API is not used to support human interaction with an application, e.g. to edit, post, and delete the data. Human interaction with an application is achieved through GUI.
Why we need an API?
API provides many uses and advantages, main being the speed and easy sharing of the data. API enormously enhances the speed to deliver the messages and receive the responses through internet. It also makes it easy to share the data among users. Further, it increases connectivity between applications, and provides people with more information.
How API is useful to developers?
Through APIs, developers can extend the projects which are publicly available, or make their projects publicly available for the developers to extend them. The developers can extend their project by first grabbing the information from server in their own program using API, and then extend it. This helps community to take advantages of the resources and thus solve the problems together.
Types of APIs
1. Source Code APIs
Source Code APIs includes Library based APIs and Class based APIs. In Library based API, an application utilizes a library and uses functions and routines to perform several actions and tasks. In Class-based API, data is provided by coding, using object oriented languages.
2. Web Services API
Web Service APIs include REST, SOAP, XML-RPC, and JSON-RPC. These APIs provide services through the World Wide Web.
3. Hardware APIs
These API helps access hardware of devices such as model number, temperature, serial number, etc.
4. Remote APIs
These types of APIs use remote protocols such as CORBA (Common Object Request Broker Architecture).