In order to receive callbacks from our system, you need to specify 'Webhook Url' within website settings under Merchant Portal, or provide 'webhookUrl' parameter in createPayment request. In case if "webhookUrl" is passed within the payment request, it will override the static one configured in the system.
In general, we do support both static and dynamic callbacks, and you can use whatever suits your business better.
To ensure that callbacks are sent from our system, you can generate a Signing Key in your website settings. If the Signing Key is specified, callbacks from our system will include 'Signature' header with HMAC256 hash generated from JSON body and Signing Key.