Common

How long does it take to receive an asynchronous notification? If I query the transaction result after redirecting to the returnURL but before receiving the notification, how should I handle it? Will the query result always be the final status?

You can call our payment GET API as a fallback mechanism when no asynchronous notification is received.

The query returns the latest status, but not necessarily the final status.
You need to check the status field to determine if it is final.
If not final, wait for the asynchronous notification or query again later.
All final statuses will trigger asynchronous notifications to your provided webhook.

What are the outbound IP addresses for asynchronous notifications?

8.212.28.186 (Normal environment)
18.140.151.69 (Disaster recovery environment)

How is the field length in the API specification defined? Why do I getField xxx invalid format even if I didn’t exceed the length limit?

The field length is calculated in bytes under UTF-8 encoding:

English letters / digits: 1 byte each
Chinese, Japanese, Korean characters: usually 3 bytes, sometimes 4 bytes

Do not simply count characters to determine length.
For example, for a field like goodsName, if it may exceed the limit, you can truncate to "first 30 characters + ...".

When the API returns"code":"B0007","message":"Unsupported currency XXX", how to resolve it?

This means the store and its configuration do not support the specified currency.
This can only be resolved internally by EVONET. Please contact your integration manager or raise an internal support ticket.

When the API returns"code":"B0006","message":"Unsupported payment brand XXX", what should I do?

This usually means the specified payment method is not configured for the store.

Add the reported payment method to the store configuration.
It is recommended to check store payment method settings whenever this error occurs to avoid repeated issues.

Why do I getDuplicated merchantTransID when calling capture or refund APIs?

URL parameter merchantTransID = the original payment’s merchantTransID
In the request body, merchantTransInfo.merchantTransID = the new Capture/Refund order ID (different from the original payment order ID)

Is there any rate limiting when calling APIs?

For normal business traffic: No rate limiting. Resources are reviewed periodically, and capacity is increased permanently if needed.
For short-term traffic spikes (e.g., campaigns): Auto-scaling is enabled, but please inform us in advance for better preparedness.
Malicious requests: Blocked by firewall and filtering mechanisms without affecting normal business.

How to trigger a single payment method?

Pass the selected payment method’s enum value to the merchantOrderInfo.enabledPaymentMethod field. Example:

{
  "enabledPaymentMethod": ["Boost"]
}

Payment method names and logos should be displayed on your checkout page. You can download them here:
Download Payment Method Names and Logos

How long before a pending payment order expires?

We do not proactively cancel or expire orders. Status will only be updated when notified by the channel or when queried.

For example, in card payment scenarios requiring 3DS, if the 3DS link is returned but the user does not access or successfully open it, the transaction will remain in Processing status.