Integration Guide

Table Of Contents
Express Checkout Integration Guide May 2010 77
7
Implementing the Instant Update
API
The Instant Update API is a callback you can use to obtain the buyers shipping address.
z About the Instant Update API
z How the Callback Works in the Express Checkout Flow
z Following Instant Update API Best Practices
z Setting Up the Callback
z Using the Callback
About the Instant Update API
The Instant Update API is a server call to your callback server that instantly updates the
PayPal review page. It enables you to specify a URL for PayPal to call your callback server
with the buyers shipping address, so you can provide the buyer with more detailed shipping,
insurance, and tax information.
NOTE: The Instant Update API enhances the Express Checkout flow from the shopping cart
page.
Here is how the Instant Update API works:
1. When a buyer logs in to PayPal, the PayPal server calls your callback server with the
buyers default shipping address, which is stored in the PayPal system.
2. Your callback server responds with the shipping options available for that address, along
with any insurance options and tax adjustments on the order.
3. PayPal displays this information on the Review page so buyers can choose from the
options.
4. The buyers final choices are returned in the GetExpressCheckoutDetails response.
Integration Steps
Integrating the Instant Update API requires some preparation and modification to the Express
Checkout API calls.
To integrate the server API, follow these steps:
1. Set up a secure, fast web service to accept HTTP requests from PayPal. On the live site, it
needs to be secured by means of SSL.
2. Enable the callback service to process PayPal requests and send back responses.