title: How do I make Paypal's checkout process happen in a small popup?
body: <p>The Humble Frozenbyte Bundle recently ended.  Before it did, if you tried to pay for the bundle by clicking their Paypal button, a small popup window appeared, asked you to log in to PayPal, asked you to click "Yes this is the right amount to pay", and the popup closed again.  Excellent!</p>
  
  <p>I'd like to do the same thing with my application, but <strong>I can't figure out the correct Paypal flow to use</strong>.  The standard cmd=_xclick WPS checkout flow takes up the entire screen, so I know that's not what Humble Bundle put in their popup...</p>
  
  <p>To be clear, I'm not asking how to make a popup window in HTML.  I'm asking how to access a PayPal checkout flow that can <strong>fit in a small popup window</strong>, about 400x800 if I remember correctly.  If the Humble Bundle were still open I'd just look at the source code, of course!</p>
  
  <p>Thanks in advance for any tips!</p>
  
  <p><strong>Update</strong>: PayPal Digital Goods are what I was looking for.</p>
  
  <p>The (not very good) Paypal integration guide is here: <a href="https://cms.paypal.com/cms_content/US/en_US/files/developer/PP_ExpressCheckout_IntegrationGuide_DG.pdf">https://cms.paypal.com/cms_content/US/en_US/files/developer/PP_ExpressCheckout_IntegrationGuide_DG.pdf</a></p>
  
  <p>And the blogpost that I am following to try to get this working is here: <a href="https://www.x.com/blogs/matt/2011/02/15/another-digital-goods-demo">https://www.x.com/blogs/matt/2011/02/15/another-digital-goods-demo</a></p>
  
  <p>I haven't quite gotten it working yet, but it's getting me close.</p>