curl --request GET \
  --url https://sandbox-api.finpace.example/v1/accounts/{accountId}/balances \
  --header 'Authorization: Bearer <token>'

{
  "accountId": "<string>",
  "bookingBalance": {
    "amount": "12500.00",
    "currency": "EUR"
  },
  "availableBalance": {
    "amount": "12500.00",
    "currency": "EUR"
  },
  "overdraftHeadroom": {
    "amount": "12500.00",
    "currency": "EUR"
  },
  "asOf": "2023-11-07T05:31:56Z"
}