# Callback URL with IPN
**Callback URL script is similar to return URL script.** Both handle the payment status result; Unlike the return URL script, callback URL script is to **handle defer status update** or **all other non-realtime payment status updates**, such as Permata VA channel.
**Merchant must fill the Callback URL in merchant admin** in order to get those non-realtime status update from the gateway. Callback URL IPN can be activated for better merchant-payment system communication. Instead of returning all parameters from the gateway, merchant’s callback script just need to echo “CBTOKEN:MPSTATOK”, in plaintext, without double quotes or any HTML tags.
**Merchant can actually use the same script for both callback URL & return URL**, because there is only one extra parameter in callback request, in addition to return URL parameters, which is “nbcb”. Besides, an additional status code, 22 has been introduced for “pending” transaction status.
Once there is a status changed event, payment gateway will POST the following parameters to mechant callback URL. If the payment gateway could not get the actual ACK message from the merchant, it will retry for a maximum 3 times, of 15 minutes interval for each attempt.
### Callback Parameters (via POST method)
| Variable / Parameter | Type Format / Max Length | Description / Example |
| -------------------- | ------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| nbcb | 1 digit numeric | Always equal to 1, which indicates this is a callback notification from PG |
| amount | 2 decimal points numeric value | The total amount paid or to be paid for Permata VA payment request |
| orderid | alphanumeric, 32 characters | Invoice or order number from merchant system. |
| tranID | integer, 10 digits | Unique transaction ID for tracking purpose |
| domain | alphanumeric, 32 chars | Merchant ID in PG system |
| status | 2-digit numeric value |
00 for Successful payment
11 for failed status
|
| appcode | alphanumeric, 16 chars | Bank approval code. Mandatory for card payment. Certain channel returns empty value |
| error\_code | alphanumeric | Refer to the Error Codes section |
| error\_desc | text | Error message or description |
| skey | 32 chars hexadecimal string | This is the data integrity protection hash string. Refer skey section for details |
| currency | 2 or 3 chars (ISO-4217) currency code | Default currency is IDR(indicating Indonesia Rupiah) for Indonesia channels |
| channel | predefined string in system | Channel references for merchant system |
| paydate | Date/Time( YYYY-MM-DD HH:mm:ss) | Date/Time of the transaction |
| extraP\* |
optional (on request)
- for credit channel
|
JSON encoded string or array
token: 16-digit card token or Direct Debit token for merchant to store for recurring MIT (merchant initiated transaction)
fraudscreen: 1-digit integer, i.e. 1=Unknown, 2=Passed, 3=Alert, 4=Suspicious, 5=Fraud
fpx\_txn\_id: FPX transaction ID
fpx\_buyer\_name: FPX buyer name
ccbrand: Visa, MasterCard, AMEX
cclast4: Last 4-digit of card number
cctype: Credit, Debit, Prepaid
captured\_date: Date/Time of the transaction status updated from authorized to captured
|
\*Note: Values are not URL encoded
### Example of callback URL script for PHP
```php
```
## Value of "Channel" in notification and callback URL
### Card / Wallet
