using RestSharp;


var options = new RestClientOptions("https://api.sandbox.{id}.gr4vy.app/payment-method-definitions");
var client = new RestClient(options);
var request = new RestRequest("");
request.AddHeader("Authorization", "Bearer <token>");
var response = await client.GetAsync(request);

Console.WriteLine("{0}", response.Content);

{
  "items": [
    {
      "id": "<string>",
      "icon_url": "<string>",
      "display_name": "<string>",
      "long_display_name": "Credit or Debit Card",
      "method": "card_payment"
    }
  ]
}