curl --request GET \
  --url https://api.example.com/api/v1/invoices/{invoice_id} \
  --header 'x-api-key: <x-api-key>'

{
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "customer_email": "<string>",
  "amount": 123,
  "currency": "<string>",
  "status": "<string>",
  "due_date": "2023-11-07T05:31:56Z",
  "paid_at": "2023-11-07T05:31:56Z",
  "refund_amount": 123,
  "refund_status": "<string>",
  "refund_reason": "<string>",
  "created_at": "2023-11-07T05:31:56Z"
}