A payment gateway API is a set of programming instructions that allows businesses to process online payments securely. It acts as a bridge between a customer’s payment method, such as a credit card, and the merchant’s bank account. By using this API, developers can integrate payment processing into websites or mobile applications, ensuring that transactions are handled efficiently and safely. When a customer makes a purchase, the payment gateway API encrypts sensitive information, like credit card details, to protect it from fraud. It then communicates with the bank to authorize the transaction, providing a seamless experience for both the customer and the merchant. This technology is essential for e-commerce platforms and online services that require secure payment processing.