Study Guide
Table Of Contents
- PayPal Certified Developer Program Study Guide
- Contents
- List of Tables
- Online Payment Processing
- Internet Security and Fraud Prevention
- Why Every Business Should Be Concerned About Internet Fraud
- Liability for Internet Fraud
- Internet Fraud: What It Is and How It Happens
- Who Is at Risk for Online Fraud
- Reducing Exposure to Fraud
- What Banks and Card Associations Are Doing to Prevent Online Credit Card Fraud
- What PayPal Is Doing to Protect Your Business Against Fraud
- Disclosure and Compliance
- PayPal Fraud Protection Services
- Review Questions
- Getting Started With Account Setup
- API Credentials
- Name-Value Pair (NVP) API
- Express Checkout
- Direct Payment API
- Transactions
- Sandbox Testing
- Answers to Review Questions
- General Reference Information
- Glossary
- Index
Express Checkout
How Express Checkout Works
6
60 March 2008 PayPal Certified Developer Program Study Guide
The PayPal Express Checkout API calls work as follows:
1. After selecting products to purchase, the customer clicks the Checkout with PayPal
button on the merchant’s website. This allows the customer to quickly skip entering
shipping and billing information on the merchant’s website.
2. The application passes PayPal the transaction details (SetExpressCheckout), receives
the response from PayPal, and redirects the customer’s browser to PayPal.
3. The customer logs in to PayPal.
4. The customer selects a shipping address and payment method stored on PayPal, and clicks
Continue Checkout to approve the use of PayPal. PayPal redirects the customer to the
merchant’s website.
5. The application makes an API call to retrieve transaction details
(GetExpressCheckoutDetails), and receives the response from PayPal.
6. The customer finishes the checkout process on the merchant’s website, reviews the order,
and completes the order. See “Order Review Page Setup” on page 76 for recommendations
on setting up an order-review page.
N OTE: The customer always reviews transaction details and makes the final payment on
the merchant’s website. PayPal handles the payment verification and passes the
application the customer’s shipping information. PayPal never shares the
customer’s financial information with anyone.
7. When the customer places the order, the application requests payment from PayPal
(DoExpressCheckoutPayment). PayPal sends a response and sends the customer an
email receipt for the payment.
8. The application transfers the customer to the order-confirmation page, showing the details
of the transaction.
The PayPal Express Checkout program flow-of-control and integration points are summarized
in Table 6.1.
TABLE 6.1 Express Checkout Flow-of-Control and Integration Points
Customer... Merchant... PayPal...
Clicks
Checkout with
PayPal button.
Sends a SetExpressCheckout request with the
required information–estimated OrderTotal,
ReturnURL, and CancelURL–and optional fields,
such as MaxAmount.
Returns a SetExpressCheckout
response with Token.
Adds value of Token from response as a name-value
pair, and redirects the user’s browser to:
https://www.paypal.com/cgi-bin/
webscr?cmd=_express-checkout&token=
value