GTM container viewer

What a published container contains

Every site with a GTM snippet loads googletagmanager.com/gtm.js?id=GTM-…, and that file is the published container: the tags and their settings, the triggers as conditions, the variables and what they read, the consent each tag waits for, and what each custom template is allowed to do. It has to be public — a browser cannot run tags it was not sent — so reading it needs no access to anyone’s account.

What it does not contain

• Names, folders and notes. They exist only in the account, so the viewer names things by what they are.
• Drafts and workspaces. Only the live version is served.
• Paused tags’ settings. A paused tag is listed, but GTM does not publish how it was configured.
• Server-side containers. Their configuration never reaches a browser.
• Whether a tag actually fired. The file says what should happen; the requests say what did. That half is what the Tag Master extension does on the page itself.

Questions

Is it free?

Yes. It runs in your browser, needs no account and no install, and has no usage limit.

Do I need access to the GTM account?

No. It reads the published container, gtm.js, which Google serves to every visitor of every site that uses it. Access to the account is what you need for drafts, workspaces, names and version history — none of which are in that file.

Why are the tag names different from the ones in GTM?

GTM does not publish names. Each tag is named by its type and the trigger that fires it, each trigger by its conditions, each variable by what it reads.

Does anything go through tagmaster.dev?

No. Your browser requests gtm.js from googletagmanager.com directly and reads it on the page. The container ID is the only thing in the request, and none of the container’s code is run.

Can it read a server-side container?

No. A server container’s configuration is never sent to a browser. The web container that feeds it is readable, and its Google tag settings usually show where the hits are sent.