curl --request GET \
  --url https://api.sandbox.solidfi.com/v2/accounts/master_account/{master_account_id} \
  --header 'api-key: <api-key>'

{
  "id": "mas_743fa071316bc6beaf5dddfd05f49c30",
  "client_id": "cli_64c6c87ee9d609f36a6f390dc378a4ce",
  "master_account_holder_id": "mah_201e02c581a098a740456c5c19fcfcd6",
  "label": "Payments Account",
  "available_balance": "104100.41",
  "pending_credits": "1198.50",
  "pending_debits": "390.10",
  "account_number": "9545931209",
  "routing_number": "123321123",
  "sponsor_bank": "Sponsor Bank",
  "currency": "usd",
  "external_reference_id": "XV-H27LGD-FX",
  "purpose": "Payment Ops Master Account",
  "attachments": [
    {
      "label": "flow of funds doc",
      "id": "att_a8d2b191fa0e960d8e49a4bfd320e07b",
      "created_at": "2024-04-01T21:00:00Z"
    }
  ],
  "metadata": {
    "master_account_code": "001"
  },
  "status": "open",
  "timestamps": {
    "created_at": "2024-04-01T21:00:00Z",
    "updated_at": "2024-04-02T21:00:00Z",
    "closed_at": "2024-04-03T21:00:00Z"
  }
}