Personally I think the paypal developer site is as confusing as they come.
I have a custom php shopping cart all working - What I need now is to add paypal payment to it. I have a lot of custom products so using paypals 'add to cart' features is not acceptable.
As far as I can see my two options are: Send to paypal just one price or send to paypal the products in a custom made form (that could be easy changed by crackers). In both cases I need to know if the payment has gone through.
I have looked in to 'standard payment' and the 'IPN' payment option but I am still baffled. What should I be looking at for a checkout that already has a bunch of custom products setup ready to send to paypal? And I tried to create an account on the paypal sandbox but I cannot due to the page 'unavailable'.
If you plan on using Website Payments Standard, you would want to use the cart upload method, and then use IPN to validate that the transaction completed. Another option would be to use Express Checkout instead of Website Payments Standard. With Express Checkout you get more control over the checkout flow than you do with Website Payments Standard, and the buyer would be completing the payment on your website. You could also then rely on the API response back from the DoExpressCheckoutPayment API to validate that the payment went through, or you could also rely on IPN, or even both if you wanted to. The links below also may help to provide a better understanding, and clear up some confusion. Just let me know if you have any other questions.