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GTM checker

Free Google Tag Manager Checker

Find every Google Tag Manager container on a page, check that it loads and see which tags the published version sets up.

Paste a page address. We open it once in a real browser, find every GTM- container, watch whether its script loads and read the published container as Google serves it.

No Google login needed. We read the same public file every visitor's browser downloads, and we show IDs and tag types, not your whole setup.

We open the page once in a real browser from Germany. The site's analytics may count that visit as one page view. We click nothing and send nothing.

example.com/pricingExample
  • ContainerDetectedGTM-XXXXXXX
  • Published versionDetectedv 42
  • Second containerLikely configuredGTM-YYYYYYY
  • Consent Mode defaultLikely configured

The main container loads and is published at version 42. A second ID sits only in the noscript fallback.

What it looks for

What the GTM checker reads

Tag Manager has two halves: the snippet on the page and the container file Google serves. The check reads both and shows the evidence behind every finding.

  • gtm.js?id=GTM-XXXXXXX

    The container snippet

    The loader that asks for gtm.js with a GTM- ID. It shows the page asks for that container.

  • ns.html?id=GTM-…

    The noscript fallback

    The iframe for browsers without JavaScript. On its own it does not show the container loads for anyone.

  • version

    The published version

    Google serves every published container to anybody who asks. We read its version, and a 404 means nothing was published under that ID.

  • googtag, gaawe, awct

    What the container sets up

    Google tags, GA4 events, Google Ads conversions and remarketing, Meta pixels and other vendors, counted by type.

  • consent 'default'

    Consent settings

    A Consent Mode template with its default, and how many tags wait for an extra consent type before they fire.

  • server_container_url

    A server container

    A server_container_url means some data goes through the site's own server, which a browser cannot see.

Reading the answer

Four words, and where each one came from

Every line of the result carries one of four words, and under it the evidence at its own level. A tag seen sending data is a stronger fact than an ID seen in the HTML, and the result never passes the weaker one off as the stronger.

Detected
The browser saw it load or send a request in this visit.
Likely configured
It is in the page's code or in the published container, and nothing ran it while we watched.
Not observed
We did not see it in this visit. That is not the same as broken: it may wait for consent, a click or a server.
Unable to verify
We could not look: a bot check, an error or a page that did not open.

The levels of evidence, weakest first

  1. In the HTMLThe ID is written somewhere in the HTML the server sent.
  2. In the containerThe published GTM container, as Google serves it to every visitor, sets it up.
  3. In the code, not runThe page's code would send it, for example in a click handler, and nothing ran that code.
  4. LoadedIts script or container loaded in a real browser.
  5. Request sentThe browser sent a request with its ID or event. That shows the request left the page, not that the platform accepted it.
Troubleshooting

Why Google Tag Manager is not working: six common causes

When GTM looks installed and the tags still do not fire, the cause is usually on this list. Each card says what the checker shows when it happens.

  • 01

    The container was never published

    Google answers 404 for a container ID that has no published version. The checker asks Google for the published file and tells you when there is none.

  • 02

    Your latest changes are not live

    Edits stay in a workspace until someone presses Submit and publishes them. The result shows the version number Google serves, so you can compare it with the Versions list in Tag Manager.

  • 03

    Only the noscript part is left

    A theme update can remove the script from the head and leave the iframe after the body tag. A container found only in noscript reads as likely configured, and the result explains why.

  • 04

    The script is blocked

    A Content Security Policy that does not allow googletagmanager.com stops gtm.js from loading. When the browser asked for the container and got nothing, the result shows the request with its status or reason.

  • 05

    Two installs fire the same tags

    Two containers, or a container plus a gtag.js snippet in the theme, can send the same GA4 or Google Ads tag twice. Each container gets its own row with the tags it sets up, so an overlap is easy to spot.

  • 06

    Tags wait for consent

    Tags with additional consent settings do not fire until the banner grants them. The result counts the tags in the container that need extra consent and does not read their silence as a fault.

By hand

How to check if Google Tag Manager is installed, step by step

Four checks you can make in any desktop browser. The checker above does the first three in one visit and reads the published container too. The last one needs access to the container.

  1. Step 1

    Search the page source

    Press Ctrl+U and search for GTM-. A full install shows the ID twice: in the script in the head and in the noscript iframe right after the opening body tag.

    gtm.js?id=GTM-XXXXXXX
  2. Step 2

    Check that gtm.js loads

    In DevTools, open Network, filter by gtm.js and reload. Status 200 means Google served the container. A 404 means nothing is published under that ID.

    gtm.js → 200
  3. Step 3

    Ask the page

    In the Console, type google_tag_manager and press Enter. The object lists the containers and Google tags that started on this page.

    google_tag_manager
  4. Step 4

    Open Preview mode

    In Tag Manager, press Preview to open the site with Tag Assistant. It shows which tags fired on each event and why, and it needs access to the container.

Compared

GTM checker, Preview mode or DevTools: when to use which

Each one sees a different part of Tag Manager. Preview mode is for the person who edits the container, and the checker is for everyone else.

Needs a page address

This GTM checker

Finds every container on the page, checks that it loads in a clean browser and reads the published version: its number and the GA4, Google Ads, Meta and consent tags it sets up. No login, and a result link you can send to whoever runs the container.

Needs access to the container

Google Tag Manager Preview

Shows which tags fired and why, trigger by trigger, including changes that are not published yet. It is the tool for debugging a tag, and it does nothing for a container you cannot open.

Needs your own browser

Browser DevTools

The Network tab and the Console show everything the page loads, if you know what to look for. They run with your cookies, your consent choice and whatever ad blocker you have installed.

Questions

Google Tag Manager checker: common questions

How do I check if Google Tag Manager is installed and published?
Paste the page address above. For each GTM- ID we show where it is on the page, whether its script loaded in the browser and whether Google serves a published version, with its version number.
Why is my GTM container not loading?
The usual reasons are a container that was never published, a snippet removed from the page, a Content Security Policy that blocks googletagmanager.com, or an ad blocker in your own browser. The checker's browser has no ad blocker, so if the container loads here and not for you, look at your extensions first.
Where do I find my GTM container ID?
In Tag Manager, at the top of the workspace next to the container name. It starts with GTM- followed by letters and numbers, and it is the same ID the checker shows.
Why does a container in noscript only count as likely?
The noscript iframe runs only for visitors without JavaScript. A page can keep that fallback after the main snippet was removed, so on its own it is not proof that the container loads.
Can you see everything in my container?
We read the published container the way a visitor's browser receives it and show counts, IDs and tag types. We do not show your triggers, variables or custom code, and we cannot see unpublished workspaces or versions.
Can I check a GTM container without access to it?
Yes. Google serves every published container to every visitor's browser. The checker reads that public file and shows its version and the kinds of tags in it. Triggers, variables and custom code stay out of the result.
The page has two containers. Is that a problem?
Not by itself. Some sites run one container for marketing and one for a platform. Each gets its own row, so you can see which one loads and what each sets up.
What does a server container mean for this check?
Data sent through a server container reaches Google or Meta from the site's server. The browser sends it to the server first, and everything after that is outside what a browser can see.
Is it safe to run this on my site?
It is one visit, like one person opening one page, from a browser that names itself as SENRIKO, plus a read of the public container file from Google. It clicks nothing and sends no form. The result is kept for 24 hours and is not listed anywhere.
The other tools

The other free tools

Check a page in one tool and open the result in another without waiting again. The four tag tools share one visit, and the two consent tools share three.

Limits

What this cannot tell you

  • 01

    A tag set up in the container fires only when its trigger matches. We show what is set up, not what fires on every page.

  • 02

    Where the container takes an ID from a variable, the ID is computed in the visitor's browser and we show it as set by a variable.

  • 03

    We do not answer the cookie banner here, so tags held until consent stay silent in this check.

  • 04

    A container loaded from the site's own domain with no ID in the HTML may not be found from the page alone. The browser visit still sees it if it loads.

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