title: How to respond to paypal payment
body: <p><strong>Some context:</strong> I am developing a website with NodeJS and the Express framework. There is one section of the site where users can take the color personality test. When they're done the test, all their answers (including name, email, and other contact info) gets sent to the server through POST. The user gets redirected to a page where they can choose to pay for an evaluation of their profile with a Paypal button.</p>
  
  <p><strong>My question:</strong> how do I retrieve the information from the original test form after the IPN listener gets triggered? Should I store the user's info in a database? If I do that, I'm not sure how I would retrieve the correct user's info after the payment notification.</p>
  
  <p><strong>The process should look something like this:</strong> Users Takes Test > Results sent to server > Server redirects user to the payment page > User pays > IPN gets triggered > Do something with test results (like send an email or something).</p>