Paypal multiple IPN setup

Question

I am not 100% clear about this when using IPN for let\'s say 3 websites, and if someone with the knowledge could explain this to me according to my scenario, I will apprecia

Answer 1

There are three URLs you can provide via hidden input elements in the form, with these names:

1. notify_url: this is the URL to which all notifications for this purchase will be sent.
2. return: this is the URL to which the user will be returned on successfully completing checkout.
3. cancel_return: this is the URL to which the user will be returned on cancelling checkout at paypal.

So if you use notify_url in the button, it can be different per site, per button, and even per button render, if you have a use for such a thing.

Note that notify_url overrides whatever you set in Payment Preferences.

Regarding (2), you can also provide an rm variable as follows:

0: User is returned via GET 1: User is returned via GET with no payment variables. 2. User is returned via PUT with all payment variables returned, i.e. as an echo of what the button sent to PayPal.

I'm not clear on the difference between 0 and 1.

See PayPal HTML Variables.

EDIT In another answer at SO which I cannot now find, a PayPal person states that you can pass arbitrary arguments in the notify_url itself, which will come back the same way you sent them.