Payment gateways facilitate online transactions by acting as intermediaries between a customer, a merchant, and the payment processor. They securely transmit transaction data, ensuring that sensitive customer information is encrypted during processing. In addition, payment gateways provide fraud protection and compliance with security standards, such as PCI DSS. They support various payment methods, including credit cards, digital wallets, and bank transfers, streamlining the checkout process. By ensuring smooth and secure transactions, payment gateways significantly enhance the overall online shopping experience.