[json] JSON for List of int

I have a class

public class ItemList
{
    public long Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public List<int> ItemModList { get; set; }
}

how should i give the input JSON for list of int as it does not have a key to match its value

JSON

{
    "Id": "610",
    "Name": "15",
    "Description": "1.99",
    "ItemModList": []
}

what should I write in the ItemModList

JSON is perfectly capable of expressing lists of integers, and the JSON you have posted is valid. You can simply separate the integers by commas:

{
    "Id": "610",
    "Name": "15",
    "Description": "1.99",
    "ItemModList": [42, 47, 139]
}