DaveVdE

Console.WriteLine("Hello, World!");
Console.ReadLine();

DaveVdE

// Who needs XML anyway?
HttpConfiguration configuration = GlobalConfiguration.Configuration;
configuration.Formatters.Remove(configuration.Formatters.XmlFormatter);
configuration.Formatters.Remove(configuration.Formatters.JsonFormatter);
configuration.Formatters.Add(new MyJsonMediaTypeFormatter());

DaveVdE

public class MyJsonMediaTypeFormatter : JsonMediaTypeFormatter
{
    public override System.Threading.Tasks.Task WriteToStreamAsync(System.Type type, object value, System.IO.Stream writeStream, System.Net.Http.HttpContent content, System.Net.TransportContext transportContext)
    {
        var obj = new {d = value};
        return base.WriteToStreamAsync(type, obj, writeStream, content, transportContext);
    }
}