This article aims to explain how the basic flow of a credit card payment works:

1. On the Checkout screen, the customer chooses the credit card Payment Method to pay for their purchase.
2. Payment information is passed to the Payment Gateway. The gateway is the player responsible for ensuring that this payment is successful.
3. With the information in hand, the payment gateway passes on the required information to the Acquirer. The acquirers are responsible for settlements of financial transactions with retailers.
4. In the possession of this information, the acquirer sends the payment data to the Card Brand. The card brand determines some business rules for payments, such as the number of installments. In addition, it connects the acquirer system with the issuing banks.
5. Finally, the brand sends the payment information to the Issuing Bank. The issuing bank performs the credit analysis, checks the available limit and then authorizes or denies payment.

With the response from the issuing bank, the reverse flow is performed and the Payment Gateway receives the information if the payment has been approved or denied.

You can include the Anti-Fraud in this stream. In such case, the anti-fraud receives the gateway information that the payment was pre-authorized by the issuing bank. With the information received from the gateway, the anti-fraud sends a payment approval or denial as response. If the anti-fraud denies, the payment is canceled. If the payment is approved, the order may continue its normal flow.