If it failed the user is given a choice to try again or choose a different payment option. I only update the actual payment status of the order upon receiving an IPN update from Pay Pal.
I am actually using production environment because I can refund the transaction with minor fee.After the payment it shows an intermediate screen that automatically redirect back to the website after 10 seconds (or if the user clicks on the link manually).Post validation, buyers can be greeted with a message, emailed an order summary or status or allowed to download digital content.At the same time, merchants can update their databases about the order and keep track of the same while processing.Payment Data Transfer is getting the transaction data of the purchase that was made on paypal site and you want to fetch that on your own site and display to the user.
Also you may want to store it in your database for archive and tracking purposes.Moving forward, we would assume that you have had some level of acquaintance with both of the notification methodologies.Read a bit about them below:- Pay Pal PDT: Payment Data Transfer is a notification method in which the buyer is securely redirected back to your online store (redirect URL mentioned in the PDT setup).Pay Pal IPN: Instant Payment Notification is a way in which Pay Pal sends a GET request to a notification URL (configured from your Pay Pal account).This happens in the background and the buyers are oblivious to it."tx=transaction_token"), and the special identity token using the variable at and the value of your PDT identity token (e.g. You will also need to append a variable named "cmd" with the value "_notify-synch", for example "cmd=_notify-synch", to the POST string.