3. Handle the callback

Paga sends this to your server. You don’t call it; build an endpoint at your callback URL that accepts it.

Sent to your callBackUrl when a payment request is paid, expires or is cancelled. Check the hash, then respond with HTTP 200. Paga retries up to three times with the same notificationId, so de-duplicate on it.

Hash: notificationId + statusCode + externalReferenceNumber + state + outstandingBalance + hashKey. Format outstandingBalance with two decimal places and no commas; leave it out if it’s null.