JsonPropertyAttribute name

public class Videogame
{
    [JsonProperty("name")]
    public string Name { get; set; }

    [JsonProperty("release_date")]
    public DateTime ReleaseDate { get; set; }
}

Videogame starcraft = new Videogame
{
    Name = "Starcraft",
    ReleaseDate = new DateTime(1998, 1, 1)
};

string json = JsonConvert.SerializeObject(starcraft, Formatting.Indented);

Console.WriteLine(json);
// {
//   "name": "Starcraft",
//   "release_date": "1998-01-01T00:00:00"
// }