GTM Server-Side Inspector

About

GTM Server-Side Inspector lets you inspect GA4 Measurement Protocol hits sent from the browser to your server-side GTM container, directly overlaid on the page — no console, no separate tab, no GTM Preview required.

How it works

When you enable the extension on a site, a lightweight widget appears in the corner of the page. Every hit sent to your SST container is captured in real time and displayed with its event name, timestamp, and full parameter breakdown.

What it captures

- Hits sent via fetch(), sendBeacon(), and XMLHttpRequest from the main thread
- Hits sent via the browser's Service Worker (tagged as "Service Worker")
- Events pushed to the dataLayer during SPA navigation (tagged as "DataLayer")

Compatible with all sGTM hosting providers

The extension depends on the protocol, not the provider. It automatically detects any /g/collect or /mp/collect endpoint on a non-Google domain, regardless of where your container is hosted — Stape, AddingWell, Google Cloud Run, Firebase, or any custom infrastructure. If your setup uses a different path, you can add it manually in the extension settings.

Features

- Real-time hit list grouped by page URL
- Full parameter detail view (Params / Raw tabs)
- Event filtering: all events, ecommerce only, or page views only
- Debug hit filtering
- Hits persisted across page reloads
- Works on SPA sites

Privacy

The extension only reads network requests on sites you explicitly enable it on. No data is sent anywhere. Everything stays local.