package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.sandbox.{id}.gr4vy.app/gift-card-service-definitions/{gift_card_service_definition_id}"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("Authorization", "Bearer <token>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}

{
  "id": "qwikcilver-gift-card",
  "type": "gift-card-service-definition",
  "display_name": "Stripe",
  "fields": [
    {
      "key": "private_api_key",
      "display_name": "Private API key",
      "required": true,
      "format": "text",
      "secret": true
    }
  ],
  "icon_url": "https://cdn.gr4vy.app/stripe.svg"
}