Webhook

What is a webhook?

A webhook is an automated HTTP call — usually a POST — that one system sends to an agreed-upon URL the moment a specific event occurs. The receiver never has to keep asking for data; the source pushes the information itself whenever something new happens. That is the key difference between a webhook and a REST API: an API requires you to fetch data repeatedly (polling), while a webhook delivers data on its own as soon as the event fires.

Why does a webhook matter?

In an online store things happen constantly that other systems need to react to right away: an order is created, a payment clears, stock changes. With webhooks you avoid polling Shopify every minute to notice this — the event triggers the action in real time. That makes integrations to your ERP, inventory system, accounting, or transactional emails faster and more reliable, and it cuts down on unnecessary API calls and delays.

Common use cases

• Order handling: send new orders to an ERP or shipping system via orders/create.
• Inventory and products: sync changes with products/update or inventory_levels/update.
• App cleanup: purge customer data when an app is uninstalled via app/uninstalled.
• Notifications: trigger an email, a Slack message, or an invoice when a payment completes.

Shopify perspective

In Shopify you can create webhooks in the admin under Settings → Notifications or via the Admin API from an app. Delivery is a POST to your HTTPS endpoint — JSON by default, though XML and channels like EventBridge and Pub/Sub are also supported. Always verify the X-Shopify-Hmac-Sha256 header with your app secret so you know the call genuinely came from Shopify. Your endpoint must respond quickly with a 2xx status (typically 200); otherwise Shopify retries for up to 48 hours and then removes the subscription.