Payment gateways work in a similar way to POS systems. A user enters their credit card details and initiates the purchase by clicking the “Buy now” or “Pay now” button. A payment gateway sends a request to the issuing bank ensuring the cardholder has sufficient funds. Once the transaction is approved by the bank, the gateway sends the information about the successful purchase back to the retailer’s website, and the money is moved from the customer’s issuing bank to the merchant’s account.