Some notes on webhook integration:
1. Upon receiving the notification to your webhook url the system will expect an HTTP 200 response.
2. Only webhooks sitting on port 80 and port 443 are guaranteed to work
3. In order to register the webhook, we send a test notification to see if the webhook is configured correctly on your side. If either one of the first two points above is not satisfied, registration will fail.
4. The test notification is an empty HTTP Post (Content-Length=0)
5. We require that you test the webhook in the TEST system before configuring it for LIVE.