What is Webhook?

What is a Webhook?

Webhook is a way for one system to send an automatic HTTP request to another system when an event happens. For example, a payment provider can notify an e-commerce application that a payment has succeeded, and the application can move the order to fulfillment.

This is different from polling. With polling, the receiving system repeatedly asks, “Is there anything new?” With a webhook, the source system sends the update when the event occurs. That makes webhooks useful for near-real-time integrations.

Webhook Flow

1. An event occurs in the source system.
2. Event data is converted into a payload, often JSON.
3. An HTTP request is sent to a preconfigured endpoint.
4. The receiving system verifies the signature, processes the event, and returns a status code.
5. If delivery fails, the source system may retry.

Security and Reliability

Because a webhook endpoint is exposed to the outside world, signature verification, HTTPS, IP restrictions, idempotency keys, and retry rules matter. The same event may arrive more than once, so the receiver must handle duplicates safely. Failed events should be visible through a dead-letter queue or an operations dashboard.

Webhooks do not replace an API. APIs are used to request data; webhooks are used to notify systems about events. Event-driven workflows are often designed together with automation and API integration.

At Barlas Dijital, webhook scenarios are common in payment, shipping, CRM, and notification flows within webhook and event-driven integration work.