How do APIs work and why do we use it?

API Working

What is an API?

API is the acronym for Application Programming Interface. An API is a set of programming codes that enables data transmission between a user and an application (a software intermediate that allows applications to talk to each other). The API receives a request and gives a response as a reply. Real-life examples: users browsing web applications like Google, Facebook, YouTube, E-Commerce, etc.,

What is a Web API?

Web APIs are an open-source framework that allows developers to build web services, and the framework implements HTTP protocols (HTTP APIs). We can build Web APIs with a variety of technologies, including Java, .NET, and others. 


How Do APIs Work?

The API has a set of rules to communicate between computers, applications, or machines. The API acts as an intermediary between any two machines that want to connect for a specified task.

Imagine you are a customer in a restaurant, and you are sitting at a table with a menu of choices to order your food without a waiter. In the kitchen, they are the providers who will fulfill their orders.

You need to communicate your order to the chef, and then you will get the food delivery from the kitchen. The chef cannot deliver the food to your table because they’re cooking in the kitchen. You need someone to order your food and vice-versa. That’s where the waiter (API) enters the picture. The waiter takes your order and delivers it to the kitchen, telling them what to do, and then you will get the food. 

The waiter (API) functions as a mediator between customers (users) and the kitchen (web server). You tell the waiter what you ordered (API call), and the waiter requests it from the kitchen. Finally, the waiter (API) will provide you with your order (from the server).


Types of APIs

APIs tend to focus on web technologies, but APIs are not limited to web services. There are other web APIs that are not utilized the most, and they are just as reliable and efficient as the web API. 


“REST API” stands for “Representational State Transfer”; it is a set of architectural constraints, not a protocol or a standard. API developers can carry out REST in a variety of ways. REST is used by 70% of public API developers due to its rapid performance, reliability, and ability to scale by reusing modular components (without affecting the overall system). 

How do REST APIs work? 

REST is a type of software design that has a predetermined set of operations and gives access to the data (aka “web resource”) by using a uniform. The payload data to be delivered as defined

in the request itself. It would be formatted in a language such as HTML, JSON, or XML. In the REST API, there is a set of operations methods available for HTTP, which is the basic protocol for how browsers retrieve websites from servers. The methods include GET, POST, PUT, DELETE, and others.

The four parts of a REST API request are: 

  • URI stands for uniform resource identifier, which is the URL address (endpoint).
  • HTTP method (commonly GET or POST)
  • Headers (including authentication tokens, the data format of the response, and imposing rate limits)
  • Body (the actual data part of the request)


SOAP API stands for Simple Object Access Protocol. It is more complicated than the REST API because it requires more information upfront about security. SOAP is the API standard from the late 1990s, which tends to lack the lightweight portability and flexibility of REST. 


XML-RPC stands for extensible markup language—Remote Procedure Calls. To transfer the data, the XML-RPC protocol uses a specific XML format, and it is simpler than SOAP. Sending an HTTP request to a server that implements XML-RPC and receiving an HTTP response, in this way, a client executes an RPC. 


JSON-RPC is a JavaScript Object Notation; it is similar to XML-RPC in that it works in the same way, but this protocol uses JSON instead of XML.


ASP.NET Web API stands for Active Server Pages. NET. The ASP.NET Web API is mostly used for creating web pages and web technologies. It is a crucial tool for developers who want to create dynamic web pages using languages like C# and Visual Basic. 

ASP.NET is an expandable framework for building HTTP-based services. It can be accessed through various applications on various platforms, such as the web, Windows, Mobile, and so on. 

Uses Of a Web API 

  • The web application’s data resources are retrieved using the Web API. 
  • Web APIs allow you to create new resources and modify existing resources. 
  • Using web APIs, you can build web services that are lightweight, maintainable, and easily scalable. 
  • Web APIs facilitate the connectivity of devices and web applications. 
  • When it comes to developing resource-oriented applications, Web APIs are the best option. 

Web API Features 

  • It supports conversion-based CRUD (Create, Read, Update, and Delete) actions and works with the HTTP verbs GET, POST, and PUT. 
  • Accept header and HTTP status code are included in all responses.
  • It also supports multiple text formats like XML, JSON, etc., or else you can use your custom MediaTypeFormatter. 
  • One of the most popular Web APIs is the ASP.NET Web API. It supports the ASP.NET MVC features such as routing, controllers, auction results, etc.

Web API Version History 

Web API version 1.0 

  • Supported .NET Framework – .NET Framework 4.0
  • Coincides with – ASP.NET MVC 4 
  • Supported in – VS 2010

Web API version 2.0 

  • Supported .NET Framework – .NET Framework 4.5 
  • Coincides with – ASP.NET MVC 5
  • Supported in – VS 2012, 2013

Through this blog, you would have got a basic understanding of APIs and Web APIs. We have also covered the types of APIs and their uses. The best part about the API is that it’s open-source, so you don’t have to pay a penny to explore it.