Webhooks

A webhook is a way for one application to send real-time data to another application automatically when a specific event occurs. Unlike traditional APIs, which require one system to periodically “ask” another if something has changed (called polling), a webhook allows systems to instantly notify each other as soon as an event happens.

Here’s how it works: a developer sets up a URL endpoint on a receiving server — this is the “webhook URL.” Then, within a service or app (like Stripe, GitHub, or WordPress), the developer configures the webhook to point to that URL and selects the events they want to be notified about. For example, a webhook might be configured to send data whenever a new user registers, a payment is completed, or a form is submitted.

When the selected event occurs, the source application sends an HTTP POST request to the specified webhook URL. This request includes data (usually in JSON format) related to the event. The receiving server can then process that data however it chooses — logging it, triggering further actions, updating databases, or notifying users.

Why use webhooks?

Efficiency: They eliminate the need for continuous polling, saving bandwidth and computing resources.
Speed: They allow for near-instantaneous responses to events.
Automation: Webhooks can power workflows, alerts, and app integrations without manual intervention.
Example use cases:

A payment gateway (like PayPal) notifies your website when a transaction is completed.
A content management system (like WordPress) triggers an external backup service whenever a post is published.
A GitHub repository notifies a CI/CD pipeline to start a build as soon as new code is pushed.
Security considerations are also important. Since webhooks are open endpoints, developers often include secret tokens or HMAC signatures to verify that incoming requests are legitimate and haven’t been tampered with.

In short, a webhook is like a digital “doorbell” — instead of checking if someone’s at the door, the system rings the bell when there’s something important to know. This makes webhooks a powerful tool for building responsive, integrated, and automated systems.