Hook into paypal ipn

[medusa11365]

I need to generate keys for digital products using a third party's api. Ideally I'd like to do this as soon as authorization is received from paypal through the ipn. Is there any way I can hook into that event? I thought of using the receipt page but there's no guarantee that the purchaser will come back to the cart after going to paypal.

Thanks!
Stephanie

[medusa11365]

Is this forum no longer supported? Questions used to be answered pretty quickly in the past...I guess it may be a stupid question, I just don't have time to hunt...