Google Tag Manager Can Now Skip the Extra gtag.js Load

Google Tag Manager can now send data straight to Google Analytics, Google Ads and other Google measurement products without loading the extra gtag.js file. Google added the change to its release notes on October 12, 2026. It is opt-in, and it matters to any site that uses Tag Manager and wants less JavaScript on its pages.

What we know

  • The change: per Tag Manager's release notes, in the October 12, 2026 entry, containers can now send data "directly" to Google measurement products.
  • Why it matters: the same entry says GTM used to load extra JavaScript (gtag.js) to send data to Google destinations, which could add latency. Google ties the change to faster site performance and better data collection.
  • It isn't automatic: Google's help page on updates to the Google tag and Tag Manager, dated August 20, 2026, says optimization is recommended but optional. Users with edit, approve or publish permissions can start it.
  • How it's enabled: according to the "Optimize your Google Tag Manager container" guide, a banner appears on GTM's Overview page. A guided flow starts from there, from a destination on the map view, or from Settings. You can preview the changes, add them to a workspace, test in Preview mode and publish with Submit.
  • What's kept: the guide says event tags and triggers are preserved. If settings across several Google tags don't match, the flow asks you to choose and resolve conflicts.
  • Permissions: the August 20 page says links to Google destinations are created automatically with "Read" access by default, which can be changed. The guide adds that permissions aren't versioned.
  • What's next: Google says the Google tag (gtag.js) will "soon" get all of Tag Manager's capabilities, with no date.
  • What Google doesn't say: none of its pages give a figure for the speed gain. The list of supported destinations sits on a separate page.

What changes and what doesn't

The data path changes: an optimized container talks to Google destinations directly instead of loading gtag.js to do it. That's one less JavaScript request per page, though the real-world gain will vary by site.

Nothing changes unless you opt in. Third-party tags, such as social media pixels or chat widgets, aren't affected and still load their own code.

How to tell if this affects you

  1. Check whether your site loads both files. In Chrome, open DevTools (F12), go to the Network tab, reload and filter by "googletagmanager." If you see both `gtm.js` and `gtag/js`, your site loads both and this update applies to you.
  2. Look for the banner in your container. Open Tag Manager's Overview page. If it isn't there, your container may not have the option yet. There's no deadline.
  3. Test before publishing. After adding the changes to a workspace, use Preview mode and check Analytics' real-time report for visits and key events: form submissions, purchases, clicks on chat or phone links.
  4. Check Google Ads conversions in the same Preview session. A conversion that stops firing may not show up for days.
  5. Review permissions in user management after optimizing, since the new links are created with read access.
  6. Compare afterwards. Repeat step 1: GTM should no longer load `gtag/js`. If something breaks, Tag Manager lets you roll back to an earlier container version.
  7. If someone else manages your site, ask whether it uses Tag Manager and who can publish changes. A container change affects all of your measurement.

Related: Web Design and Development

Sources

Updates: if Google publishes speed figures, changes the destination list or gives the Google tag Tag Manager's capabilities, it will be added here with a link.