Tags, triggers and variables
A tag is the code you want to run, like a GA4 event or an ad pixel. A trigger decides when it runs, like a page view or a form submit. Variables hold values the tags and triggers need, like a page URL or an order total.
GTM vs Google Analytics
Google Analytics collects and reports data. Tag Manager is the delivery system that sends data to Analytics and other tools. Many sites use both together.
Why teams use it
Marketers can add or fix tracking quickly, test changes in preview mode and keep a version history, without waiting on a developer for every update.
Why Google Tag Manager matters
Clean tag management keeps analytics and ad tracking accurate. A messy container full of old or duplicated tags can slow your site and quietly corrupt your data.
The banner that broke checkout
A store added a consent banner through GTM without testing it on mobile. The banner covered the checkout button and orders dropped until the tag was fixed. Testing in GTM's preview mode before publishing would have caught it.
Common mistakes
Publishing without testing
Use preview mode to check that tags fire correctly before publishing changes.
Letting the container grow messy
Old, unused and duplicate tags pile up. Review and clean the container regularly.
Too many people with publish access
Limit who can publish. One bad change can break tracking or the site itself.
Where we work on this