DefaultValueHandling setting

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public Person Partner { get; set; }
    public decimal? Salary { get; set; }
}

Person person = new Person();

string jsonIncludeDefaultValues = JsonConvert.SerializeObject(person, Formatting.Indented);

Console.WriteLine(jsonIncludeDefaultValues);
// {
//   "Name": null,
//   "Age": 0,
//   "Partner": null,
//   "Salary": null
// }

string jsonIgnoreDefaultValues = JsonConvert.SerializeObject(person, Formatting.Indented, new JsonSerializerSettings
{
    DefaultValueHandling = DefaultValueHandling.Ignore
});

Console.WriteLine(jsonIgnoreDefaultValues);
// {}