Webhooks are HTTP POST requests from external services notifying your application about events — a Stripe payment succeeding, a GitHub push, or a PayPal subscription renewing. As the creator of CoreUI with 25 years of backend development experience, I’ve built webhook handlers for payment processors, version control systems, and communication platforms where reliability and security are critical. The two non-negotiable requirements are: verify the webhook signature before processing, and return 200 immediately then handle the event asynchronously. Failing to verify signatures exposes you to spoofed events; slow synchronous processing risks timeouts and missed retries.

A payment API in Node.js needs to create payment intents, handle webhook events from the payment provider, and update order status atomically when payment is confirmed. As the creator of CoreUI with 25 years of backend development experience, I’ve built payment integrations for e-commerce platforms where a missed webhook means a customer paid but their order was never fulfilled. The safest pattern creates a pending order, creates a Stripe payment intent referencing that order, and then fulfills the order only when Stripe confirms payment via webhook. This decoupled approach handles network failures and browser closures gracefully.