using System;

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        var data = new BookingJsonModel() 

        {

           Id = Guid.NewGuid(),

           Reference = "blub"

        };

        var body =  Newtonsoft.Json.JsonConvert.SerializeObject(data);

        Console.WriteLine(body);

    }

    [JsonObject(Title = "booking")]

    public class BookingJsonModel

    {

        [JsonProperty("id")]

        public Guid Id { get; set; }

​

        [JsonProperty("reference")]

        public string Reference { get; set; } = null!;

    }

}