Catch Tracking Bugs Before They Corrupt Data (DebugView)

Why this matters

Analytics bugs are invisible until they corrupt weeks of data — DebugView and event validation let you catch missing parameters, wrong event names, and double-firing tags in real time before they reach production reports.

Try it yourself

1. Enable debug_mode: true on your GA4 tag in GTM, trigger a purchase event on a staging environment, and verify in DebugView that all required parameters (transaction_id, value, currency, items) appear with correct types.
2. Deliberately send an event with a parameter value exceeding GA4's 100-character limit and observe how DebugView truncates or drops it — note the exact character count where truncation occurs.
3. Use GA4's event count card in DebugView alongside a browser network tab filtered to collect? requests — confirm every network request produces exactly one event row in DebugView, ruling out double-firing.

References

• https://support.google.com/analytics/answer/7201382