When using PayPal as your payment processor for Zen Cart, there are a few payment modules in "Zen Cart admin -> Modules -> Payment" for you to choose from...
In this article, we will talk about the differences between the PayPal IPN module and the PayPal Express Checkout module. The PayPal Website Payments Pro module requires signing up with the PayPal Website Payment Pro service which requires a monthly fee to Paypal. The other two modules that we will talk about does not require a monthly fee.
This PayPal IPN module is ZenCart's implementation of the PayPal Website Payments Standard service. This service has been designed to be compatible with many third-party shopping carts including Zen Cart.
From a customer's point of view, the customer goes through the three steps of checkout in Zen Cart's checkout pages. After the third confirmation step, the customer is redirected to a PayPal-hosted page where he/she enters his/her credit/debit card payment. On this PayPal hosted page, the customer can also choose to pay by PayPal by logging into their PayPal account. After payment, the customer is redirected back to Zen Cart's thank you page.
One drawback of this payment module is that the product line items that the customer had purchased is not shown in the PayPal's invoice that is emailed to the administrator whenever an order has been placed. However, the product line items are shown in the ZenCart invoice that is emailed to the administrator as well as in the orders records in the ZenCart admin control panel.
A couple of relevant quotes in this Zen Cart forum thread says ...
"If you want detailed line-item invoices in PayPal, then turn off the Website Payments Standard(IPN) module, and enable Express Checkout."
and ...
"The Standard/IPN module treats the order as a payment receipt, not as a detailed per-item order invoice. The invoice is at your store for them to reference if needed. If you want it to show detailed line-item listings of all products in the purchase, use Express Checkout instead."
As its name implies, PayPal express checkout is ZenCart's implementation of PayPal's Express Checkout Service.
This service has been designed to be compatible with many third-party shopping carts including Zen Cart.
However in order to use this service, you have to follow PayPal's button placement and usage requirements. This requires you to place the orange PayPal checkout button on your shopping cart page as well as everywhere else where you have a checkout button on your site. You have to display PayPal as the default payment option. Then you have to place a "Now Accepting PayPal" banner button next to your "add to cart" buttons. And if your site requires user to sign in (which ZenCart does), there should be a PayPal Express Checkout button there.
By using the Zen Cart Express Checkout Payment module, you will see the orange button appear in the shopping cart page ...
and in the login page ...
Some merchants who prefer not to have PayPal promoted so extensively throughout their site can use the PayPal IPN module instead, which does not require these PayPal button placements.
Another drawback to the PayPal express checkout is the strict validation of the billing and shipping address of an order. Sometimes when a customer does not type in the address in proper format the transaction may fail.
For example, in this forum thread, it says ...
"It appears it gives the error because there are two capital letters in one word. If I change it to Du Bois, I no longer get the error."
As quoted in another thread, "PayPal does a comparison of ZIP + State + City for validation" If validation does not pass, PayPal redirects the user back to Zen Cart where it displays this error to the user: "The address information you entered does not appear to be valid or cannot be matched"
In addition some people have experienced error 10413 and a few said that switching to Website Payment Standard resolved the issue. Some relevant quotes from this forum thread are ...
"Just an update on my struggle to get PayPal to work properly
Paypal express - dumped.
PayPal website payments standard - working. This module all worked perfect from the start, not sure why its so confusing to get express working but I'm more than happy with WPS."
"Any updates on this 10413 problem, I have just switched to PayPal Express from Standard payments that worked fine!"
"At this point, I'm going to recc. to my client to drop PEC beacuse of these 10413 errors."
This article was written in October 2009 and refers to version 1.3.8 of Zen Cart.
