Beginner's Guide to ASP NET Core Web API Tutorial in Visual Studio 2026

Welcome to this comprehensive guide on creating a Web API in ASP.NET Core using Visual Studio 2026. If you're new to ASP.NET Core and eager to dive into building Web APIs, you've come to the right place.

ASP.NET Core is a cross-platform, high-performance, and open-source framework for building modern, cloud-based, Internet-connected applications. Its Web API framework makes it easy to build HTTP services that can be consumed by a wide range of clients, including browsers and mobile devices.

Setting Up Your Environment

Before we delve into creating our Web API, let's ensure you have the necessary tools installed.

First, ensure you have Visual Studio 2026. If you don't, you can download it from the official Microsoft website. During installation, make sure to select the ".NET desktop development" and "ASP.NET and web development" workloads.

Creating a New ASP.NET Core Web API Project

Once Visual Studio 2026 is installed, open it and click on "Create new project". In the search bar, type "asp net" and select the "ASP.NET Core Web API" template.

On the next screen, name your project (e.g., "MyFirstWebApi"), select a location to save it, and click "Create". Then, choose ".NET 6.0" (or later) and click "Create" again. Finally, click "Create" once more to create the project with minimal authentication.

Exploring Project Structure

Let's briefly explore the generated project structure. In the Solution Explorer, you'll find the following folders:

• Controllers: Contains the controller classes that handle HTTP requests/responses.
• Models: Stores the data models used in your API.
• Properties: Contains launchSettings.json, which configures your API's URLs and ports.

The WeatherForecastController.cs file under the Controllers folder contains a basic example of a controller. We'll modify this to create a simple API.

Building Your First ASP.NET Core Web API

Let's create a simple API that returns a list of items when a GET request is made.

First, let's create a model. Right-click on the "Models" folder, select "Add" > "Class", name it "Item.cs", and add the following code:

```csharp public class Item { public int Id { get; set; } public string Name { get; set; } } ```

Creating a Controller

Next, replace the code in WeatherForecastController.cs with the following:

```csharp using System.Collections.Generic; using Microsoft.AspNetCore.Mvc; using MyFirstWebApi.Models; [ApiController] [Route("[controller]")] public class ItemsController : ControllerBase { private static List _items = new List { new Item { Id = 1, Name = "Item 1" }, new Item { Id = 2, Name = "Item 2" }, // Add more items as needed }; [HttpGet] public ActionResult> Get() { return _items; } } ```

This code creates a simple API that returns a list of items when a GET request is made to /items.

Testing Your API

To test your API, press F5 to start the application. Once it's running, open your browser and navigate to https://localhost:/items. You should see a JSON response with the list of items.

Congratulations! You've just built your first ASP.NET Core Web API. This is just the beginning of your journey with ASP.NET Core. The next steps involve learning about creating more complex APIs, implementing authentication, and much more.

Now that you have a solid foundation, the world of Web APIs in ASP.NET Core is open to you. Happy coding, and remember to keep exploring and building amazing things! 🚀💻