A payment gateway is a technology that facilitates online transactions between customers and merchants. It securely processes credit card and other payment information, ensuring that sensitive data is encrypted and transmitted safely. This allows businesses to accept payments through their websites or mobile apps without compromising customer security. When a customer makes a purchase, the payment gateway communicates with the bank or financial institution to authorize the transaction. Once approved, the funds are transferred from the customer's account to the merchant's account, completing the sale. This process is essential for e-commerce and helps streamline online shopping experiences.