Establishing interaction with the payment gateway
The interaction with the payment gateway works in the same way as in the case of classic single payment, namely via exchanging HTTP forms.
To create a payment, this data is sent in an HTML form via the buyer’s browser.
- Automatically by means of notifications called Instant Notification URLs (also called IPN or Instant Payment Notification), see chapter Setting up notifications.
- Via the browser, when the buyer clicks the button to return to the merchant website, see chapter Managing the return to the merchant website.
To guarantee the security of the exchange, the data is signed with a key known only by the merchant and the payment gateway.