This plug-in allows Grails applications to integrate with Paypal and its Instant Payment Notification (IPN) system. A PayPalController is provided that has a "notifyPaypal" action which deals with responses from the PayPal IPN. In order for this to function you need to enable IPN in your PayPal Profile under Profile / Instant Payment Notification Preferences and provide PayPal with the URL you have mapped the "notify" action to. In order for this plug-in to function you must configure the ...