Dates without time in ASP.NET Web API's JSON output

Is there a simple way to configure JSON.NET so that some DateTime fields will be formatted without time and other DateTime fields will still be formatted with time?

Example:

{ firstName: 'John', lastName : 'Doe', birthday: '1965-09-23' }

If you need this to only affect a particular field, create a converter type first:

public class OnlyDateConverter : IsoDateTimeConverter
{
    public OnlyDateConverter()
    {
        DateTimeFormat = "yyyy-MM-dd";
    }
}

and then add this attribute to whatever fields/properties you want this for:

[JsonConverter(typeof(OnlyDateConverter))]

Try adding this line to configure your Web API:

config.Formatters.JsonFormatter.SerializerSettings.Converters.Add(
    new IsoDateTimeConverter() { DateTimeFormat = "yyyy-MM-dd" });