curl --request GET \
  --url https://external.vin.gs/api/v1/spending/merchants/top \
  --header 'Authorization: Bearer <token>'

{
  "totalExpense": {
    "amount_cents": 123,
    "currency": "<string>"
  },
  "merchants": [
    {
      "merchant": "<string>",
      "total": {
        "amount_cents": 123,
        "currency": "<string>"
      },
      "percentOfTotal": 123,
      "transactionCount": 123
    }
  ]
}