Establishing interaction with the payment gateway

The merchant website and the payment gateway interact by exchanging data.

To create a payment, this data is sent in an HTML form via the buyer’s browser.

At the end of the payment, the result is transmitted to the merchant website in two ways:

  • Via the browser when the buyer clicks the button to return to the merchant website.
  • automatically by means of a notification called Instant Notification URL (also called IPN), see chapter Setting up the end of payment notification.

To guarantee the security of the exchange, the data is signed with a key known only to the merchant and the payment gateway.