Integration Guide

Table Of Contents

HTML Form Basics for PayPal Payments Standard

Instant Payment Notification – notify_url

416 June 2012 PayPal Payments Standard Integration Guide

How IPN Works – Three General Steps

1. A payment or a refund triggers IPN. This payment can be via PayPal Payments Standard

FORMs or via the PayPal Web Services APIs for Express Checkout, MassPay, or

RefundTransaction. If the payment has a “Pending” status, you receive another IPN when

the payment clears, fails, or is denied.

2. PayPal posts HTML FORM variables to a program at a URL you specify. You can specify

this URL either in your account profile or with the notify_url variable on each

transaction. This post is the heart of IPN. Included in the notification is the payment

information, such as the payer’s name and the amount paid. All possible variables in IPN

posts are detailed in the

Instant Payment Notification Guide. When your server receives a

notification, it must process the incoming data.

3. Your server must then validate the notification to ensure that it is legitimate. For details,

see the

Instant Payment Notification Guide.