Integration Guide

Table Of Contents
Express Checkout Integration Guide May 2010 83
Implementing the Instant Update API
Setting Up the Callback
7
GetExpressCheckoutDetails and DoExpressCheckoutPayment Changes
When you implement the callback, you need to call GetExpressCheckoutDetails and
DoExpressCheckoutPayment.
GetExpressCheckoutDetails and DoExpressCheckoutPayment include new
parameter fields in support of the Instant Update API.
You must call the GetExpressCheckoutDetails API operation to obtain the buyer’s final
shipping option selections. GetExpressCheckoutDetails has been updated to return the
buyers selections.
Because the cart information passed in the call to SetExpressCheckout is only relevant for
display on the PayPal Review page, you must call the DoExpressCheckoutPayment API
operation with the updated shipping, insurance, and tax data to ensure the buyer sees it upon
redirect to your website.
Other Considerations
When you implement the callback, there are other issues you must take into consideration.
These include:
z Callback response errors
z Minimum and maximum shipping options
z Callback times out
z You do not ship to the buyer’s shipping address
Callback Response Errors
If there are any callback response errors, PayPal responds by displaying the flat-rate shipping
options on the PayPal Review page. To obtain the richer set of options available through the
callback, exercise care in the syntax and values you specify and test the callback integration.
Minimum and Maximum Shipping Options
You can specify up to 10 shipping options for the flat-rate options in the call to
SetExpressCheckout and for the detailed options based on shipping address in the callback
response. You must specify at least 1 shipping option.
Callback Times Out
If the callback does not return within the timeout period, PayPal displays the flat-rate shipping
options you specified in the call to SetExpressCheckout in the drop-down menu on the
PayPal Review page.
The PayPal Review page in the figure below shows 2 shipping options from which the buyer
can choose if the callback times out. An amount of $1.00 is offered for insurance.