GA4 Debugger by agnarok

GA4 Debugger adds a dedicated "📶 GA4 Debugger" panel to Firefox DevTools so you can see exactly what your Google Analytics 4 implementation is sending — in real time, without digging through the Network tab.

Every GA4 event is captured as it fires (including events sent via the Beacon API, which the Network panel often hides) and displayed in a clean, color-coded list. Click any event to expand a full breakdown organized into five columns:

• Event — event name and all custom event parameters (ep. / epn.)
• User — Client ID, User ID, consent state, and user properties
• Session — session ID, session count, hit counter, engagement
• Settings — Measurement ID, protocol version, GTM hash, page hash, language
• Platform — browser, OS, architecture, and screen/viewport (decoded from User-Agent Client Hints)

FEATURES
• Real-time GA4 event capture, including sendBeacon and first-party / server-side GTM endpoints
• Event-type filters: Custom, Pageview, Automatic, Ecommerce, Recommended
• Filter events by name
• Debug Mode — routes events to GA4 Admin → DebugView
• Test Mode — blocks GA4 requests so your test traffic never pollutes production analytics data
• Copy any event's full payload as JSON
• Expand-all toggle for fast scanning

PRIVACY
GA4 Debugger does not collect, store, or transmit any data. Everything is parsed and shown locally inside DevTools and discarded when you close the panel. No external servers, no tracking.

Open source: https://github.com/agnarok/ga4-debugger-firefox