# IPN

### Instant Payment Notification

Merchant receive refund result. Similar to [ipn](https://docs.neox.vn/docs/payment-gateway/transaction-management/ipn "mention")

Merchant has to respond to NeoX  following the structure [merchant response](#merchant-response) when receiving IPN.

#### IPN verification

Merchant needs to build a hashed string follow above guide and compare to received *neo\_SecureHash* parameter

Method: POST

### NeoX's IPN data

<table><thead><tr><th width="200">Parameter</th><th width="117">Data type</th><th>Description</th></tr></thead><tbody><tr><td>neo_MerchantCode</td><td>String</td><td>The merchant code is  provided by NeoX.</td></tr><tr><td>neo_Command</td><td>String</td><td>"REFUND"</td></tr><tr><td>neo_OrderID</td><td>String</td><td>Order ID</td></tr><tr><td>neo_PaymentID</td><td>String</td><td>ID of payment record</td></tr><tr><td>neo_RequestID</td><td>String</td><td>Request ID sent to NeoX in refund request</td></tr><tr><td>neo_TransactionID</td><td>String</td><td>Unique - Transaction ID is generated by NeoX.</td></tr><tr><td>neo_Amount</td><td>Number</td><td>Refund amount.</td></tr><tr><td>neo_Fee</td><td>Number</td><td>Refund fee</td></tr><tr><td>neo_Version</td><td>String</td><td>Payment gateway version, “1” as default</td></tr><tr><td>neo_ResponseCode</td><td>Number</td><td>Result of transaction: <br> 0: transaction success <br> != 0: transaction failed, refer to <a href="../../../transaction-management/error-codes#table-of-error-code">table of error code</a></td></tr><tr><td>neo_ResponseMsg</td><td>String</td><td>Error description.</td></tr><tr><td>neo_SecureHash</td><td>String</td><td>Use <strong>SHA256</strong> to hash the above parameters (sort the key by Alphabet order) + Secret Key (is provided by NeoX after actual integrating).</td></tr></tbody></table>

```
{
  "neo_MerchantCode": "UFLIYL",
  "neo_Command": "REFUND",
  "neo_OrderID": "DH7255715767",
  "neo_PaymentID": "1439211",
  "neo_RequestID": "a68de39f-ea76-43fb-848f-b605b4aaf44e",
  "neo_TransactionID": "XBSKM1OELUDU",
  "neo_Amount": 10000,
  "neo_Fee": 3300,
  "neo_Version": "1",
  "neo_ResponseCode": 0,
  "neo_ResponseMsg": "Success",
  "neo_SecureHash": "3C97E508CBED7561759D049C5FA58BE2DE455EA4E7EE07B1DFDF2AFC4783E144"
}
```

### Merchant response

<table><thead><tr><th width="158.33333333333331">Parameter</th><th width="162">Data type</th><th>Description</th></tr></thead><tbody><tr><td>respcode</td><td>Number</td><td><ul><li>0: Successful, merchant received IPN.</li><li>1: Failed, NeoX will retry the IPN. </li></ul></td></tr><tr><td>respmsg</td><td>String</td><td>Error message. Default is “<em>received</em>”</td></tr></tbody></table>