using System;

using Newtonsoft.Json;

using Newtonsoft.Json.Serialization;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

                ""full_name"": ""John Smith"",

                ""total_price"": ""20.00""

            }";

        var settings = new JsonSerializerSettings

        {

            ContractResolver = new DefaultContractResolver { NamingStrategy = new SnakeCaseNamingStrategy() } 

        };

        var dto = JsonConvert.DeserializeObject<InputObjectDTO>(json, settings);

        Console.WriteLine("FullName: " + dto.FullName);

        Console.WriteLine("TotalPrice: " + dto.TotalPrice);

    }

}

​

public class InputObjectDTO

{

    public string FullName { get; set; }

    public decimal TotalPrice { get; set; }

}