8

Adding PayPal to Your Third 

party Shopping Cart 

Some web developers want to integrate PayPal payment processing with their own third party 

shopping cart instead of the standard PayPal Shopping Cart. The instructions and variables in 

this chapter allow your buyers to pay with PayPal when they are ready to check out after 

adding all of their items to your third party shopping cart.

There are two ways to integrate your third party shopping cart with the PayPal payment flow:

1. Pass to PayPal the details of the individual items that have been selected

2. Pass the aggregate amount of the total cart payment, rather than the individual item details.

For a complete list of variables, see 

 HTML Samples and Buy Now, Donations, and Shopping 

Cart Variables  on page 127

.

N

O T E

:

Posting the necessary variables to PayPal as described in the following instructions 

might require you to implement some scripting on your website.

Passing Individual Items to PayPal

If your third party shopping cart can be configured to pass individual items to PayPal, 

information about the items will be included in the buyer's and seller's History transactions 

and notifications. To include information about the items, you will post HTML form elements 

to a new version of PayPal's Shopping Cart flow. This process is much like the one described 

in Passing Aggregate Shopping Cart Amount to PayPal, with the following exceptions:

1. Set the cmd variable to _cart.

For example, if you are modifying PayPal Buy Now HTML, you might replace this 

required HTML line:

with

2. Add the upload variable:

3. Define item details.

For each of the following item specific parameters, define a new set of values that 

correspond to each item that was purchased with your third party cart. Append _

x

 to the 

Website Payments Standard Checkout Integration Guide

August, 2005

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