Glossary
Webhook
An HTTP request a service sends to a URL you control the moment something happens — a real-time, event-driven callback instead of you repeatedly asking 'anything new?'
A webhook is a user-defined HTTP callback. You register a URL with a provider (Stripe, GitHub, Shopify); when an event occurs, the provider sends an HTTP POST to that URL with a JSON body describing what happened. It's 'inverse API' — instead of you calling them on a schedule, they call you the instant there's news.
Webhooks trade polling's latency and waste for a new set of concerns: you must verify each request is genuine (signatures), handle retries and duplicate deliveries (idempotency), and stay reachable or lose events while your endpoint is down.
The mental model: a webhook is a one-way notification, not a request/response conversation. The provider expects a fast 2xx to acknowledge receipt — do the real work asynchronously and acknowledge first.
How HookSense helps
HookSense gives you a webhook URL in one second so you can see exactly what a provider sends — headers, body, signature — before you write a single line of handler code.
Get a free webhook URL