This sample demonstrates the in-memory hosting of an ASP.NET Web API application.

program.cs

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

namespace WebApiInMemoryHost
{
    class Program
    {
        static void Main(string[] args)
        {
            RunAsync();
        }

        private static async Task RunAsync()
        {
            HttpConfiguration config = new HttpConfiguration();
            config.Routes.MapHttpRoute("DefaultHttpRoute", "api/{controller}");
            using (HttpServer httpServer = new HttpServer(config))
            using (HttpClient httpClient = new HttpClient(httpServer, false))
            {
                Console.WriteLine("Started the server!");
                while (!Console.ReadLine().Equals("q", StringComparison.InvariantCultureIgnoreCase))
                {
                    Console.WriteLine("Sending the request...");
                    HttpResponseMessage response = await httpClient.GetAsync("http://host/api/cars");
                    string[] cars = await response.Content.ReadAsAsync<string[]>();

                    foreach (string car in cars)
                    {
                        Console.WriteLine(car);
                    }
                    Console.WriteLine("Done!");
                }
            }

            Console.WriteLine("Closed the server!");
        }
    }

    public class CarsController : ApiController
    {
        public string[] GetCars()
        {
            return new[] 
            { 
                "Car 1", 
                "Car 2", 
                "Car 3" 
            };
        }
    }
}