using System;

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        string json = @"{ ""applicationId"": ""123"", ""vaultGuid"": ""some-guid"", ""newestAllowedKey"": ""some-key"", ""createdOnUtc"": ""2023-04-15T12:34:56.789"" }";

        dynamic bodyData = JsonConvert.DeserializeObject( json );

        string createdOnUtcString = bodyData.createdOnUtc;

        Console.WriteLine("bodyData.createdOnUtc as a string:" + createdOnUtcString);

        DateTime res = DateTime.Parse(createdOnUtcString);

        Console.WriteLine("We cannot get milliseconds from that:" + res.ToString("yyyy-MM-ddTHH:mm:ss.fff"));

        Console.WriteLine("No milliseconds:" + res.Millisecond);

    }

}