title: Paypal API Question - Can I use Return Url to verify payment
body: <p>I'm trying to create a simple paypal purchase system. Going through a few tutorials, it seems like I need to use the IPN (Instant Payment Notification) system to keep track of whether the order is paid.</p>
  
  <p>Is it sufficient to use the return url variable instead, and pass in the order id? For example, something like return="http://mysite.com/paid?id=5&amp;pass=xyS2y"</p>
  
  <p>The variables - <a href="https://cms.paypal.com/us/cgi-bin/?&amp;cmd=_render-content&amp;content_ID=developer/e_howto_html_Appx_websitestandard_htmlvariables" rel="nofollow noreferrer" title="PayPal HTML Variables">PayPal HTML Variables</a></p>