Why Doesn't an E-Commerce Payment API Get Called Twice When Users Double-Click the Pay Button? (opens in new tab)

Introduction Imagine you're purchasing a product online. You click the "Pay Now" button, and due to a slow internet connection or impatience, you accidentally click it again. A common question among developers is: If two requests are sent, why doesn't the payment get processed twice? The answer lies in a combination of frontend protection, backend safeguards, database design, and payment gateway architecture. In this blog, we'll explore how modern e-commerce systems prevent duplicate payments...