Ask HN: How does Groupon or Grubwith.us do their group payment system?

[jaytee_clone]

I have heard that they don't use PayPal. And I cannot imagine the hassle of rolling your own system. Any ideas? Maybe WePay?

[failquicker]

I believe they are using a custom interface from Braintree. Pretty sure living social is the same.

[jaytee_clone]

I will check them out. Thanks a lot.