ContractResolver setting

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }

    public string FullName
    {
        get { return FirstName + " " + LastName; }
    }
}

Person person = new Person
{
    FirstName = "Sarah",
    LastName = "Security"
};

string json = JsonConvert.SerializeObject(person, Formatting.Indented, new JsonSerializerSettings
{
    ContractResolver = new CamelCasePropertyNamesContractResolver()
});

Console.WriteLine(json);
// {
//   "firstName": "Sarah",
//   "lastName": "Security",
//   "fullName": "Sarah Security"
// }