DataLayer Debugger

About

DL Debugger is a live dataLayer inspector for marketers, analysts, and developers working with Google Tag Manager (GTM) and GA4.

Every time something is pushed to window.dataLayer, the extension logs it to your browser console with a clean, colour-coded badge so you can see what is happening at a glance. No more typing dataLayer.slice() into the console or rummaging through nested arrays.

KEY FEATURES

→ Live console logging
   Every dataLayer.push call is shown as a collapsible group with a sequence number, timestamp, event name, and a short summary of the most relevant parameters.

→ Smart categorisation
   Events are colour-coded by type: ecommerce (purchase, add_to_cart, view_item, etc.), pageview, form, GTM internals, gtag calls, consent updates, and custom events. You can tell at a glance whether a fire matters.

→ gtag() detection
   The extension correctly parses gtag() calls that push their arguments object, so you see "gtag:set user_properties" instead of a confusing list of numeric keys.

→ Exportable reports
   Open the popup and export everything captured so far as:
   • Self-contained HTML report (filterable, searchable, with summary cards and full payload drill-down)
   • Raw JSON (for programmatic processing)
   • CSV (for spreadsheets)

→ Live stats popup
   Click the toolbar icon to see a live count of events captured, events-per-second rate, category distribution bar, and the last 5 events ticking in real time. Includes an in-popup search to filter the feed.

→ Pause and resume
   Click the LIVE pill to pause capture on a site. Pause state persists across page reloads and navigations. There is also a "Pause everywhere" toggle that disables the extension across every site until you turn it back on.

→ Built for noisy real-world sites
   Re-entrant push calls (common when GTM wraps the push method) are de-duplicated. DataLayer replacement (common during GTM init) is detected and re-patched automatically. Non-serialisable values (functions, DOM nodes, circular references) are safely handled in the export.

WHO IS THIS FOR

→ GTM implementors validating that the right events fire
→ Analytics engineers debugging GA4 ecommerce schemas
→ QA testers checking tracking on release branches
→ Performance marketers verifying tag triggers
→ Developers adding new dataLayer events to a site

WHY USE THIS ALONGSIDE GTM PREVIEW

GTM Preview is excellent for seeing which tags fire from which trigger. DL Debugger sits one layer earlier in the stack: it shows the raw dataLayer pushes feeding those triggers, and it lets you export them. Use both together for full visibility: Preview for tag debugging, DL Debugger for the data layer itself.

PRIVACY

DL Debugger does not collect, transmit, or store any data outside of your browser. Captured events stay in the memory of the tab you are debugging, and the export reports are generated locally. No analytics, no remote calls, no account required.

DOCS AND SUPPORT
https://www.mohitkumars.com/ga4-gtm-utils/datalayer-debugger