Problem Diagnosis: You Will Never Think As Stupid As Users

blog.bendauphinee.com

I prefer the use pattern where all details of the transaction are summarized to the user, who is invited to press "Confirm".

It's fairly strange behavior for your client's customers to have to enter in an identical value twice. Maybe use an API that allows you to programmatically generate and the send the invoice?

All transactions are summarized on the invoice page, then they are able to click a button that sends them to PayPal, with their invoice number and grand total as part of the information sent. There is no entering data twice.

I assume you are speaking of when I talked of users entering their cost on PayPal. This was due to them not selecting anything to buy, but continuing to PayPal with a "Grand Total: $0" invoice anyway

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