What is a webhook in server-side tracking?

Webhooks are lightweight, event-driven code snippets that enable real-time communication between applications. In the context of server-side tracking, webhooks provide a reliable way to send data from external systems (such as CRMs or CMSs) to server environments like Google Tag Manager (sGTM), allowing for more accurate and flexible event tracking.

How do webhooks work?

A webhook’s code typically consists of:

• Webhook URL: specifies the endpoint where your data should be delivered.
• Payload (body): contains the core information you want to transmit to the receiving application.
• Headers: provide metadata about the request, like the content format (commonly JSON or XML), to ensure the receiving system understands how to interpret the data.
• Request method: usually set to POST, though other HTTP methods like GET, PUT, or DELETE may be used depending on the type of action being performed.

Webhooks operate on a simple principle: 

1. A predefined event occurs in a system, e.g., a new user registers or a purchase is made. 
2. The system sends an HTTP request, typically a POST, to a designated URL (webhook endpoint). This URL belongs to a webhook server that listens for such requests.
3. Webhook endpoint processes the payload data to trigger appropriate actions like updating databases, firing tags, or sending data to analytics platforms.

Benefits of webhooks

Unlike APIs, which require constant polling to check for updates, webhooks push data as soon as an event happens. This push-based communication model makes webhooks ideal for server-side tracking, especially when tracking events outside the web browser, such as phone orders, offline sales, or CRM updates.

• Real-time event delivery: instantly receive data without delays.
• Reduced load: eliminate the need for continuous API polling.
• Automation: seamlessly trigger downstream processes, such as updating CRMs or sending offline conversions to ad platforms.
• Improved attribution: track conversions that originate offline or outside the browser.
• Security: server-side webhooks reduce reliance on client-side scripts, offering greater control over data flow.

How to set up webhooks

Specific webhook setup depends on your tracking configuration. If you want to learn more, see this article for an example of how to set up webhooks for event tracking.