using System;

using System.Text.Json;

public class Program

{

    public static void Main()

    {

        var model = new

        {

            Name = "Alexander"

        };

        var serializedModel = JsonSerializer.Serialize(model);

        var deserializedModel = JsonSerializer.Deserialize<HasName>(serializedModel);

        SomeExternalLib.Foo(deserializedModel);         

    }

}

​

class SomeExternalLib

{

    public static void Foo(object o)

    {

        var nameProperty = o.GetType().GetProperty("Name");

        var name = nameProperty.GetValue(o);

        Console.WriteLine("I got the name: " + name);

    }

}

​

class HasName

{

    public string Name { get; set; }

}

​