Choosing the POST method will deliver the full results via the customer’s browser as a form post back to the CallbackURL. This is usually the least difficult method to implement. The downside is, if the CallbackURL does not begin with HTTPS (notice the significance of the S), then the connection is not secure. If that is the case, most modern browsers throw a security warning to the customer explaining that sensitive information is being passed over to an insecure connection. We do not send sensitive information back, but the browsers are trying to safeguard the customer. As a result, we show the customer a dialog informing them of the reason why they are about to see a security warning and how to handle it.

The next two Server Result Methods exchange the transaction results directing with the merchants system and the payment page (removing the customer’s browser from the process).