by Doug


Google Analytics

Explain GTM – Google Tag Manager Containers in plain English


We had an incredible week in Hungary at SuperWeek at the start of February. This conference was superbly described as a festival of data and analytics. Couldn’t agree more. Either kick your year off with a trip to Hungary in 2017 or try out more SuperWeek experiences later this year. You won’t regret it.

I talked about a tool we wrote to help explain Google Tag Manager. tl;dr – There is a list of use cases where [we feel that] the current GTM UI either doesn’t support the required functionality or can be improved. We have total respect and admiration for the GTM team so rather than batter them with feature and change requests we decided to build a tool to demonstrate what we’re on about. We call it Explain GTM because that’s what it does.
It turns out this tool is actually pretty handy so we want to share it with the world.
The full deck is available here.

6 Use Cases

  1. Search. Don’t just search for assets – search in assets. Want to find which event tag is sending a certain event action? Want to find all the tags where a custom metric is being sent? Use the flexible search tool to find assets by name and assets that mention strings using contains, exact and reg ex matching.
  2. You need to review a GTM container but can’t get access (new client?). Get an export, upload it to Explain GTM and review it without having to plead for access. Nice and safe.
    Bonus: Why not hit the ‘Expand everything’ button and save a GTM dictionary as a pdf document (
  3. What tags and/or triggers are using a variable? You no longer need to delete an asset to see what’s using it. Tags, triggers and variables all have a “Where it’s used” section to help you navigate the container.
  4. Not technical? Don’t worry, Explain GTM translates as much as possible to plain English. It’s not just a tool for expert practitioners – we want everyone to get value from GTM.
  5. If you use tag sequencing or firing priorities you can see an overview of the values used to help you sequence tags with more finesse.
  6. Want a super fast audit of a container? Explain GTM will list all the known advisories to help surface common ‘gotchas’.
  7. BONUS +1: Want a super fast export of a large container? You can get an export REALLY quickly using explain GTM.

Using it
You’ve got three options:

  1. Go to and paste a container export in the obvious place. Hit process:

  2. Use the bookmarklet. Create a bookmarklet using this script:
    javascript:(function(o,m,g){ g=o.getElementsByTagName(m)[0];var j=o.createElement(m);j.async=true;j.src=’//’;g.parentNode.insertBefore(j,g);})(document,’script’);
    Then when you’re in GTM looking at a container overview or even a specific asset, click the bookmarklet. You’ll see this dialog pop up:

    Now you can use version 0 to ‘Explain’ the container being edited or use any version number available:

    When the “Explain GTM to me” button appears, use that or use the “Copy to clipboard” to grab a super fast container export.

  3. Fork and host your own. Full source available here:
    The repo contains all the php, HTML and js you’ll need. It’s also got a container export that you can use to measure your own version. Change the container ID in the markup of course. The gtm2en.js file referenced in the bookmarklet is included for you to host – change the domain used in the bookmarklet as required.

Remember, this is free. It’s not commercial software so it might contain bugs or need refinement. We always appreciate thanks and/or suggestions so positive and constructive feedback is the order of the day.
We hope you find this tool useful too.

Maybe, one day, it’ll be a thing of the past as GTM will contain all the features demonstrated in the tool. You never know


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