Introduction to APIs

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The device that turns a website’s data into something a computer can understand is an API. Similar to how a person may access and modify data by loading pages and submitting forms, a machine can view and edit data through it.

Making data easy to deal with is beneficial since it allows programmers to automate laborious and time-consuming operations. Through an API, a computer may complete tasks that would normally take a person hours to complete.

How to Use an API

We refer to two systems as being “integrated” when they connect via an API (websites, desktops, cellphones). You have two sides in an integration, each with a unique name. The API is actually provided by this side. It is useful to keep in mind that the API is just one more server-side application. It might be a component of the online traffic management package or something entirely else. In either scenario, it is idle and waiting for someone to request data from it.

The “client” is on the opposing side. This is a different application that is aware of the data that is accessible via the API and has the ability to change it, usually at the request of a user. A smartphone app that syncs with a website is a fantastic example. Your program uses an API to communicate with a server and retrieve the most recent information when you press the refresh button.

The Protocol of the Web

There is a protocol for almost everything, and each one is designed to do a certain task. Some of them, like Bluetooth for syncing devices and POP or IMAP for retrieving emails, you may already be familiar with.

The Hyper-Text Transfer Protocol, or HTTP as it is more often known, is the primary protocol used on the internet. The “http” instructs the browser to communicate with the server according to the HTTP standards when you type a URL like into a web browse

HTTP Requests

The RequestResponse Cycle is a notion at the heart of HTTP communication. A request is made by the client to the server. In response, the server notifies the client as to whether it could fulfill the request made by the client.

To make a valid request, the client needs to include four things:

1 URL (Uniform Resource Locator)

2 Method

3 List of Headers

4 Body


We are all aware of URLs from using the internet every day, but have you ever given their structure some thought? A URL is a specific address for an object in HTTP (a noun). The company administering the server determines which items receive addresses. They are able to create URLs for websites, pictures, and even videos of adorable animals.


The request method informs the server of the type of action the client desires. The approach is frequently referred to as the request “verb” in actuality.

The four methods most commonly seen in APIs are:

1. GET – Asks the server to retrieve a resource

2. POST – Asks the server to create a new resource

3. PUT – Asks the server to edit/update an existing resource

4. DELETE – Asks the server to delete a resource


Headers offer meta-data regarding a request. They consist of a short list of details like the client’s request’s time stamp and body size.


The information the client wishes to transmit to the server is in the request body. The body is where the specifics of the order go.

The client has complete control over this portion of the request, which makes the body special. The HTTP protocol does not impose any strict structure on the method, URL, or headers, but permits the client to send everything it needs in the body.

The URL, method, headers, and content are the only components that make up a whole HTTP request.

HTTP Responses

When the server receives a request from the client, it makes an effort to process the request and reply to the client. The structure of HTTP answers and requests is strikingly similar. The answer now includes a status code rather than a method and URL, which is the primary difference. Beyond that, the body and headers of the response have the same structure as a request.

How APIs Build on HTTP

You can now see that HTTP allows a variety of variants to aid communication between the client and server. How does this assist us with APIs, then?

Due to HTTP’s adaptability, APIs developed on it can provide clients a lot of commercial possibilities. The HTTP protocol is flexible in other areas of a request as well. While some APIs want a certain header, others require specific data in the request body. Understanding how to send the right HTTP request to obtain the desired result is essential for using APIs.


Application Programming Interface, or API, is an acronym for a group of protocols and routines that different programs use to communicate with one another. A programmer can utilize a variety of API tools to simplify and ease the development of their program. Additionally, an API gives programmers a productive way to create their software.

Written by 

Mohd Uzair is a Software intern at Knoldus. He is passionate about java programming. He is recognized as a good team player, a dedicated and responsible professional, and a technology enthusiast. He is a quick learner & curious to learn new technologies. His hobbies include watching movies, surfing youtube, playing video games.