Why is DPS calling my success/fail url TWICE in succession?
This is deliberate redundancy – see http://www.paymentexpress.com/blue.asp?id=d_pxaccess, under “Fail Proof Result Notification”. By doing this when a customer submits a credit card for processing your site is guaranteed to receive notification of the transaction. Without this feature there would likely be a problem if a cardholder failed to return to the merchant site having submitted a card e.g. he might close his browser. Generally merchants, quite properly, rely on this notification to know when to take action on orders. The two calls we make to the URL are identical, so we advise developers to simply disregard the second post if and when they get it.
