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GTM / Pixel Checker

Keep a list of client URLs with their expected GTM containers (as many as each site uses) and Meta Pixel ID. It audits them every day and flags anything missing, mismatched, or not firing.

🏷️

Install the Browser Extension

Click the toolbar icon to open the dashboard. Add URLs one at a time or paste a whole list from a spreadsheet. Hit Run Audit, or let it run by itself every day. Each site gets a clear label: All Good, GTM Not Found, Pixel ID Mismatch, Not Firing, and so on.

Download Extension (.zip)

🌐 Install on Chrome

  1. Unzip the downloaded file to a folder you'll keep (e.g. Documents).
  2. Open chrome://extensions in a new tab.
  3. Toggle Developer mode on (top-right).
  4. Click Load unpacked and select the unzipped folder.
  5. Pin the extension via the puzzle icon, then click it to open the dashboard.

🔷 Install on Edge

  1. Unzip the downloaded file to a folder you'll keep.
  2. Open edge://extensions in a new tab.
  3. Toggle Developer mode on (left sidebar).
  4. Click Load unpacked and select the unzipped folder.
  5. Pin the extension via the puzzle icon, then click it to open the dashboard.

What each label means

All Good GTM Not Found Pixel Not Found GTM ID Mismatch Pixel ID Mismatch GTM Not Firing Pixel Not Firing Page Error Blocked by Ad Blocker

A tag only counts as firing when a real network request goes out: the gtm.js container loads, or a facebook.com/tr beacon carrying your Pixel ID is sent. An ID that's in the code but never fires usually means a cookie consent banner is holding it back.

How the daily audit works

At the time you choose, the extension opens each URL in a background tab inside a minimized window. It watches the page's network traffic, reads the page source, and closes the tabs when it's done. If Chrome was closed at that time, the audit catches up the next time you open Chrome. You can also get a notification when something needs attention.

Everything stays in your browser. Your URL list and results live in the extension's local storage, and you can export or import them as config.json. Heads up: an ad blocker in the same browser also blocks GTM and the Pixel during audits. The extension detects this and labels it, so allow-list your client sites or use a Chrome profile without a blocker.