A minimal fully asynchronous C# ASP.NET Core 3.0 application with routing (learn more about ASP.NET Core here https://docs.microsoft.com/en-us/aspnet/core/?view=aspnetcore-3.0)

Program.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Hosting;

public class Program
{
    public static void Main(string[] args) =>
        Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.Configure(app =>
            {
                app.UseRouting();
                app.UseEndpoints(route =>
                {
                    route.MapGet("/", context => context.Response.WriteAsync("Hello world"));
                });
            });
        })
        .Build().Run();
}

WebApp.csproj

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <TargetFramework>netcoreapp3.0</TargetFramework>
  </PropertyGroup>
</Project>

@BuddySpike Such a ridiculous comment. No disrespect, but I find it hard to not see the elegance in the code presented here. Sure, can C#/.NET claim it has as small a surface area as Go? Absolutely not. The language has been maturing for almost 20 years, .NET roughly the same. But, if you're programs are backed by .NET Core chances are you're writing fast, succinct and simple-to-reason-about software. If you want to stick around at the handler level, we call them RequestDelegate's, you absolutely can. The built in router, or mux if you want to be silly and fancy, is fantastically designed and has auto parameter mapping built-in (no slicing through the URL.path required).

@davidfowl Love this! Such an emphasis on bare bones these days, and I feel as though .NET is sometimes still viewed as cumbersome. Which I don't believe is the case at all.

Created a version without the default host builder, to make things a bit more explicit for potential newcomers. Seeing this as a potential acorn for new projects!