The purpose of an online payment gateway is to facilitate secure, electronic transactions for e-commerce and online services. It acts as the intermediary between a merchant's website and the customer's bank, processing credit card payments and ensuring that sensitive financial data is transmitted securely. Payment gateways encrypt transaction information and verify payments, reducing fraud risks. Additionally, these gateways often provide features such as recurring payments, multi-currency support, and integration with various e-commerce platforms. By streamlining payment processes, online payment gateways enhance user convenience and trust, ultimately supporting business growth.