Is PayPal IPN suitable for verification of auctions if you are auction website owner

I am developing an auction website. When a person intents to pay for an auction item, I pass his 开发者_高级运维email_id and that of the seller to Paypal and then invoke IPN through notify_url. Once he pays the data is sent to my IPN listener so that I process and update the database. My question is; since I am a third party, if the seller has disabled IPN will I receive the variables on my IPN listener? If not how else can I ensure that I get confirmation of payment and process the database. I cant use return_url because it is dependent on whether the buyer returns to my site.

When using notify_url that will override any setting they have in their PayPal account for IPN, so you'll be fine for the most part.

The place you might have an issue is when somebody has their own IPN listener they want to use, or some other 3rd party solution that also requires it. You'll need to setup a way for your users to include additional IPN URL's and then forward the same IPN data on to those 3rd party URL's if that becomes an issue.