What is an API? Full Form, Learn how to use APIs, In this Tutorials for Beginner step by step?

What is an API?

Application Programming Interface (API) is a software interface that allows two applications to interact with each other without any user intervention. API is a collection of software functions and procedures. In simple terms, API means a software code that can be accessed or executed. API is defined as a code that helps two different software’s to communicate and exchange data with each other.

It offers products or services to communicate with other products and services without having to know how they’re implemented.

How does API work?

APIs work by sharing information and data between applications, systems, and devices—making it potential for these items to speak with one another.

Sometimes the simplest thanks to admit APIs is to admit a trope, and a typical state of affairs that loads of parents use is that of the client, a waiter, and a eating place kitchen: A client talks to the waiter and tells the waiter what she desires. The waiter takes down the order and communicates it to the room. The room will their work, making the food, then the waiter delivers the order back to the client.

In this trope, a client is sort of a user, United Nations agency tells the waiter what she desires. The waiter is like associate degree API, receiving the customer’s order and translating the order into easy-to-follow directions that the room then uses to meet that order—often following a selected set of codes, or input, that the room simply acknowledges. The room is sort of a server that will the work of making the order within the manner the client desires it, hopefully! once the food is prepared, the waiter picks up the order and delivers it to the client.

REST full API best practices come down to four essential operations:

  • Receiving data in a convenient format
  • Creating new data
  • Updating data
  • Deleting data

REST relies heavily on HTTP. We will not explain the features of this protocol, but it is worth mentioning its great advantage in this situation.

Each operation uses its own HTTP method:

  • GET– requests data from a server. This is the most common type of request. Using it we can get the data we are interested in from those that the API is ready to share.
  • POST– adds new data to the server. Using this type of request, you can, for example, add a new contact to CRM
  • PUT– changes existing information. For example, using this type of request, it would be possible to change the color or value of an existing product.
  • DELETE– deletes existing information.

All these methods (operations) are generally called CRUD. They manage data or as Wikipedia says, “create, read, update and delete” it.

Why would we need an API?

Here, are some reason for using API:

  • Application Programming Interface form API helps two completely different software’s to speak and exchange knowledge with one another.
  • It helps you to introduce content from any web site or application more efficiently.
  • APIs will access app parts. The delivery of services and data is information is more flexible.
  • Content generated can be published automatically.
  • It permits the user or a corporation to customize the content and services that they use the foremost.
  • Software need to change over time, and genus APIs to anticipate changes.

Benefits of APIs

APIs allow you to save time when developing and help not to invent a bicycle.

It is much more efficient and more convenient to use the capabilities of one of the APIs than to try to independently implement similar functionality.

Moreover, it will be problematic to get some functions and data other than through the API (for example, a weather forecast, a thematic selection of news or a high-quality translation from almost any language).

APIs recharge your applications with the latest technology. With APIs, you can teach your application the latest image recognition and natural language processing methods.

Features of API

Here are some important features of API:

  • It offers a valuable service (data, function, audience,.).
  • It helps you to plan a business model.
  • Simple, flexible, quickly adopted.
  • Managed and measured.
  • Offers great developer support.

Types of API

There are mainly four main types of APIs:

  • Open APIs: These types of APIs are publicly available to use like OAuth APIs from Google. It has also not given any restriction to use them. So, they are also known as Public APIs
  • Partner APIs: Specific rights or licenses to access this type of API because they are not available to the public.
  • Internal APIs: Internal or private. These APIs are developed by companies to use in their internal systems. It helps you to enhance the productivity of your teams.
  • Composite APIs: This type of API combines different data and service APIs. It is a sequence of tasks that run synchronously as a result of the execution and not at the request of a task. Its main uses are to speed up the process of execution and improve the performance of the listeners in the web interfaces.

Communication level of APIs:

Here, are some communication level of APIS:

High-Level APIs:

High-level APIs are those that we can generally use in REST form, where programmers have a high level of abstraction. These API’s mostly concerned about performing a limited functionality.

Low-Level APIs:

This kind of APIs has a lower level of abstraction, which means they are more detailed. It allows the programmer to manipulate functions within an application module or hardware at a granular level.

What is Web APIs?

A Web API is an application programming interface which is use either for web server or a web browser.

Two types of Web APIs are 1) Server-side API 2) Client-side API


Server-side web API is a programmatic interface that consist of one or more publicly exposed endpoints to a defined request–response message system. It is typically expressed in JSON or XML


A client-side web API is a programmatic interface helps to extend functionality within a web browser or other HTTP client.

Examples of web API:

  • Google Maps API’s allow developers to embed Google Maps on webpages by using a JavaScript or Flash interface.
  • YouTube API allows developers to integrate YouTube videos and functionality into websites or applications.
  • Twitter offers two APIs. The REST API helps developers to access Twitter data, and the search API provides methods for developers to interact with Twitter Search.
  • Amazon’s API gives developers access to Amazon’s product selection.

API Testing tools

Here are some popular API tools:


Postman is a plugin in Google Chrome, and it can be used for testing API services. It is a powerful HTTP client to check web services. For manual or exploratory testing, Postman is a good choice for testing API.


  • With Postman, almost all modern web API data can be extracted
  • Helps you to write Boolean tests within Postman Interface
  • You can create a collection of REST calls and save each call as part of a collection for execution in future
  • For transmitting and receiving REST information, Postman is more reliable.

Download link: https://www.postman.com/


  • The full form of API is Application Programming Interface.
  • API is defined as a software code that helps two different software’s to communicate and exchange data with each other.
  • API helps you to plan a business model
  • Five types of API are 1) Open API 2) Partner API 3) Internal API 4) High-level 5) Low-level API
  • A Web API is an application programming interface which is use either for web server or a web browser.
  • There are two types of web APIs 1) Server Side API 2) Client Side API
  • Some popular API testing tools are 1) Postman 2) Ping API and 3) vRest.

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