Question about connecting QIWI?

Question

Payment systems

Who has qiwi connected by the form method or the http method.
Interested in how you inform your system about the connection of payment? Because qiwi does not send a request to a secret URL (like webmoney for example), the address with the payment status via curl is not available - there, on JS, authorization is still needed. The page that is redirected to after a successful payment is public and available to everyone - not an option...