using System;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(JsonConvert.SerializeObject(new TestData(), new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.Objects }));

        var typedJson = @"{""$type"":""Program+TestData, ConsoleApp2"",""TestField"":0}";

        var testData = JsonConvert.DeserializeObject(typedJson, new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.Objects });

        var json = JsonConvert.SerializeObject(testData);

        Console.WriteLine(json);

    }

​

    public class TestData

    {

        public int TestField;

    }

}