using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        string json = @"{

              ""exemptBenefits"": [

                 ""1"",

                 ""0"",

                 ""true"",

                 ""false"",

                 ""yes"",

                 ""no"",

                 ""YES"",

                 ""something else"",

                 ""TRUE"",

                 null

              ],

              ""_apiEndpoint"": ""/benefits/loan""

            }";

        var loan = JsonConvert.DeserializeObject<Loan>(json);

        Console.WriteLine(string.Join("\r\n", loan.ExemptBenefits.Select(b => b.HasValue ? b.Value.ToString() : "null")));

    }

}

​

class Loan

{

    [JsonProperty(ItemConverterType = typeof(NullableBoolDeSerializer))]

    public List<bool?> ExemptBenefits { get; set; }

}

​

class NullableBoolDeSerializer : JsonConverter

{

    readonly string[] TrueStrings = { "true", "yes", "1" };

    public override bool CanConvert(Type objectType)

    {

        return objectType == typeof(bool?);

    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

    {

        string b = (string)reader.Value;

        return b != null ? TrueStrings.Contains(b.ToLower()) : (bool?)null;

    }

    public override bool CanWrite

    {

        get { return false; }

    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

    {

        throw new NotImplementedException();

    }

}

​