2012
Table Of Contents
- Instant Payment Notification Guide
- Contents
- Preface
- Introducing IPN
- Implementing an IPN Listener
- Identifying Your IPN Listener to PayPal
- IPN Testing
- IPN Operations on PayPal
- Using Fraud Management Filters With IPN
- IPN Variable Reference
- IPN Transaction Types
- Transaction and Notification-Related Variables
- Buyer Information Variables
- Payment Information Variables
- Auction Variables
- Mass Pay Variables
- Recurring Payments Variables
- Subscription Variables
- Dispute Resolution Variables
- Pay Message Variables
- Preapproval Message Variables
- Adaptive Accounts IPN Messages
- Payment Review Using Notifications
- Revision History
Introducing IPN
A Sample IPN Message and Response
14 July 10, 2012 IPN Guide
PayPal-Initiated IPN Messages
Some IPN messages generated by PayPal are not directly associated with a web flow. PayPal
generates an IPN message when external events arise that might affect a transaction, such as
disputes, chargebacks, echeck clearing, and various recurring payment and subscription
events.
In this case, events that trigger IPN messages are not directly related to actions on your
website. The following diagram shows the steps your listener must take:
The numbers in diagram correspond to the following steps, which implement the IPN message
authentication protocol:
1. PayPal sends your IPN listener a message that notifies you of the event
2. Your listener sends the complete unaltered message back to PayPal; the message must
contain the same fields in the same order and be encoded in the same way as the original
message
3. PayPal sends a single word back, which is either VERIFIED if the message originated with
PayPal or INVALID if there is any discrepancy with what was originally sent
After successfully completing the protocol, your back-office or administrative process vets the
contents of the message and responds appropriately. For example, the IPN messages may
trigger you to print shipping labels for items whose payments have cleared, investigate
disputes and chargebacks, store information in an accounting system, and so on.
A Sample IPN Message and Response
An IPN message consists of variables that describe the transaction. These variables contain
information about you, your customer, and the details of the transaction itself.
PayPal sends a message, similar to the following one, for a $19.95 purchase made by Express
Checkout: