Every e-commerce website needs a payment processing system, and PayPal is the most widely used processing system in the world. If you're a web developer, being able to implement a PayPal Instant Notification System is a must have skill for your toolbox. What Is PayPal IPN? PayPal IPN is used for managing orders and creating transaction reports. Instant Payment Notification is a message service that automatically notifies merchants of events related to PayPal transactions. Merchants can use it to automate back-office and administrative functions, like fulfilling orders and providing customers with order status. Who Should Take This Course? Every web developer on the planet! To take this course you should have a basic knowledge of PHP programming.