using System;

using System.Text.Json;

using System.Text.Json.Serialization;

public class Program

{

    public static void Main()

    {

        var json = "{\"name\": \"Dennis\"}";

        var thing = JsonSerializer.Deserialize<Thing>(json);

        Console.WriteLine($"Hello {thing.Name}");

    }

}

​

public class Thing

{

    public Thing(string name) => this.Name = name;

    [JsonPropertyName("name")]

    public string Name {get;}

}

​