Tagalong
A tag injector for QA.
Bring your tag manager container along to any site. Check it there without changing the site’s code.
Start here
Open Tagalong on the page you want to test.
Add the site and enter a container ID you control.
Grant access when Chrome asks. The popup may close while the prompt is open.
Reload the page. A green ON badge means the container is on the page.
In the page’s own console, window.__tagalong shows the container ID, whether the script loaded, and any errors. Inspect the site itself. The popup has a separate window.
What the popup shows
- Whether the container script loaded, and any error it hit.
- Other container IDs already on the page.
- The latest data layer events, and a QA summary you can copy.
- A link to Tag Assistant, from the same card.
Advanced options stay folded: iframes, a custom data layer name, preview parameters, a server-side loader URL, events to push first, replacing the site’s container, and removing the content security policy. Settings apply on the next full load.
When something’s wrong
The page blocked the script
Turn on “Remove content security policy” for that site, then reload. That removes the page’s script restrictions for the sites on that container.
The script didn’t load
Check the container ID, then reload. The ID looks like GTM- followed by 4 to 12 letters or digits.
The page has two containers
Turn on “Replace the site’s container” if you only want yours, then reload. That blocks other copies of the tag manager script on those sites.
Tagalong skips browser pages, the Chrome Web Store, and PDFs. It asks for access only for the sites you add.
Still stuck?
A tracking audit looks at the container, the page, and the numbers. Tell me what you were trying to test.