curl --request GET \
  --url https://api-beta.pepay.io/api/commerce/merchant/carts \
  --header 'x-commerce-api-key: <api-key>'

{
  "success": true,
  "data": {
    "merchantId": 123,
    "customerId": "<string>",
    "walletAddress": "<string>",
    "walletNetwork": "<string>",
    "items": [
      {}
    ],
    "subtotal": 123,
    "itemCount": 123,
    "createdAt": 123,
    "updatedAt": 123
  }
}