JsonDifferenceDetector

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Text.Json;

var p = new JsonDifferenceDetector();
JsonDifferenceDetector.Main(new string[]{});
public class JsonDifferenceDetector
{
    public static void Main(string[] args)
    {
        var x = new Example(){a = 1, b = "2", c = DateTime.Now};
        var y = new Example(){a = 1, b = "two", c = DateTime.Now.AddDays(1)};

        Compare(x, y);
    }

    public static void Compare(Example x, Example y)
    {
        var jso = new JsonSerializerOptions(){WriteIndented = true};
        string xs = JsonSerializer.Serialize(x, jso);
        string ys = JsonSerializer.Serialize(y, jso);

        // Console.WriteLine(xs);
        // Console.WriteLine(ys);

        Regex keyValue = new Regex("\"(?<key>\\w+)\": (?<val>.+)(,|)$");
        string[] xArr = xs.Split("\n");
        string[] yArr = ys.Split("\n");
        for (int i = 0; i < xArr.Length; i++)
        {
            var xLine = xArr[i];
            var yLine = yArr[i];
            if (xLine == yLine)
            {
                continue;
            }

            Match xm = keyValue.Match(xLine);
            Match ym = keyValue.Match(yLine);

            string key = xm.Groups["key"].Value;
            string xv = xm.Groups["val"].Value;
            string yv = ym.Groups["val"].Value;

            Console.WriteLine($"{key}: {xv} -> {yv}");
        }
    }
}
[Serializable]
public class Example
{
    public int a { get; set; }
    public string b { get; set; }
    public DateTime c { get; set; }
}