dotnet CSharp asp.net core web api rest beginners dotnet 101

Creating and Consuming REST APIs

API basics with ASP.NET Core and C# clients

Posted by Rodrigo Castro on December 28, 2024

REST APIs let applications communicate over HTTP. In .NET, you can both build APIs (servers) and consume them (clients).

🛠️ Creating a REST API (ASP.NET Core)

Create a project:

dotnet new webapi -n MyRestApi
cd MyRestApi

Add a sample controller:

[ApiController]
[Route("[controller]")]
public class ProductsController : ControllerBase
{
    [HttpGet]
    public IEnumerable<string> Get() => new[] { "Apple", "Banana" };
}

Test with Swagger:
Run dotnet run and visit /swagger.

🌐 Consuming a REST API (C# client)

Use HttpClient to make HTTP requests:

using System.Net.Http;
using System.Threading.Tasks;

var client = new HttpClient();
var response = await client.GetAsync("https://api.example.com/products");
var json = await response.Content.ReadAsStringAsync();
Console.WriteLine(json);

🔑 Tips

Use HttpClientFactory for better performance in production apps.
APIs often use JSON; you can deserialize using System.Text.Json.

Next: Using HttpClient in more detail!