curl --request GET \
  --url https://api.example.com/customer/accounts/balance/{account_id} \
  --header 'X-API-NONCE: <x-api-nonce>' \
  --header 'X-API-SIGNATURE: <x-api-signature>' \
  --header 'X-API-SUBSCRIPTION-KEY: <x-api-subscription-key>' \
  --header 'X-API-TIMESTAMP: <x-api-timestamp>'

{
  "message": "<string>",
  "data": {
    "account_id": "57g3dnEZXOFgYN4yCSVitRcV",
    "account_number": "0999999",
    "available_balance": {
      "amount": 123,
      "currency": "<string>"
    },
    "held_balance": {
      "amount": 123,
      "currency": "<string>"
    },
    "total_balance": {
      "amount": 123,
      "currency": "<string>"
    },
    "system_timestamp": "2025-05-16T18:16:45.088469926Z"
  }
}