Building a REST API in C#: A Step-by-Step Guide with Source Code

Category > ASP.NET MVC || Published on : Thursday, March 2, 2023 || Views: 42 || REST API C# web services HTTP methods Visual Studio model class controller class database connection Postman source code step-by-step guide.

Here Pawan Kumar will explain how to Build a REST API in C#: A Step-by-Step Guide with Source Code

C# is a popular programming language used to develop a wide range of applications, including web and mobile applications. With the rise of the internet and the increasing popularity of web services, the use of REST APIs has become more common. In this article, we'll explore what a REST API is, why it's important, and how to build one using C#.

What is a REST API?

REST stands for Representational State Transfer. It's a web service architecture that allows different systems to communicate with each other over the internet. REST APIs use HTTP methods like GET, POST, PUT, and DELETE to perform various operations on the data.

REST APIs are stateless, which means that each request is independent of previous requests. This makes it easier to scale and maintain the system. REST APIs also use a uniform interface, which means that the same interface is used for all resources, making it easier to understand and use.

Why are REST APIs important?

REST APIs are an essential component of modern web development. They allow developers to create applications that can communicate with each other, enabling data exchange between different systems. REST APIs can be used for a wide range of applications, including social media, e-commerce, and online banking.

Building a REST API in C#

Building a REST API in C# is relatively straightforward. Here are the steps you need to follow:

Step 1: Create a new project

To get started, open Visual Studio and create a new C# project. You can choose the project template that best suits your needs.

Step 2: Install the necessary packages

To build a REST API in C#, you need to install some necessary packages. These packages include Microsoft.AspNetCore.App, Microsoft.VisualStudio.Web.CodeGeneration.Design, and Microsoft.EntityFrameworkCore.SqlServer.

Step 3: Create a model class

The next step is to create a model class that represents the data you want to expose through the API. For example, if you're building a REST API for a music application, you might create a model class for songs, with properties like artist, title, and album.

public class Song
    public int Id { get; set; }
    public string Artist { get; set; }
    public string Title { get; set; }
    public string Album { get; set; }

Step 4: Create a controller class

The controller class is responsible for handling incoming HTTP requests and returning responses. In this example, we'll create a SongsController class that exposes a GET endpoint for retrieving songs.

public class SongsController : ControllerBase
    public IEnumerable<Song> Get()
        // retrieve songs from the database
        return _context.Songs.ToList();

Step 5: Configure the application

To configure the application, you need to set up a database connection and specify the routes for the API endpoints.

public void ConfigureServices(IServiceCollection services)

    services.AddDbContext<SongContext>(opt =>

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    if (env.IsDevelopment())


    app.UseEndpoints(endpoints =>

Step 6: Test the API

To test the API, you can use a tool like Postman. Send a GET request to the endpoint specified in the controller class, and you should receive a response containing the data you specified in the model class.


In conclusion, building a REST API in C# is a great way to create web services that can communicate with other systems. REST APIs are an essential component