GA4 & Google Tag Manager Duplicate Tag Checker
Inspect any website for duplicate Google Analytics 4 (GA4) Measurement IDs, conflicting GTM containers, legacy Universal Analytics scripts, and real-time network beacons.
Why Duplicate GA4 & GTM Tags Silently Sabotage Ad Spend
When a GTM container fires a GA4 tag while a hardcoded gtag.js snippet also remains in the HTML, every pageview and conversion is double-counted. Our headless Chromium engine distinguishes between standard GTM head/noscript pairs, GTM-injected tags, and genuine duplicate declarations.
- Detects GTM containers (GTM-XXXX), GA4 Measurement IDs (G-XXXX), and Google Ads conversion tags (AW-XXXX)
- Separates active HTML script declarations from GTM runtime container injections to prevent false positives
- Verifies real network beacon transmissions to google-analytics.com and googletagmanager.com