Google Tag Manager
In short
Google Tag Manager is a management layer for measurement and marketing code. Instead of embedding each script in the site, the site holds one container and everything else is managed and published inside it. It measures nothing itself — it only decides which code loads when.
The problem it solves
Dependency. Without it, every change to measurement needs a code change and a deployment. With it, that becomes a publish that takes minutes.
The second gain is visibility. Every script sits in one place instead of scattered through the source. Code nobody can find is code nobody can switch off.
What it explicitly is not
Not an analytics tool. It produces no metric at all — those come from whatever it loads, typically Google Analytics.
And not a substitute for a measurement plan. Decide which events count and what they are called, or you get tidy management of an untidy data model.
Where setups fail
On naming. An event that exists under three spellings cannot be added up later, and the mistake only surfaces when someone needs the first report.
The second common case is duplication: a script sits in the container and in the source code as well. Every visit then counts twice, and the numbers look better than they are. Only a comparison against the measurement plan catches it.
How we handle it
We fix event names before implementation and verify after it that each event fires exactly once. Measurement goes live only then.
Measurement and reporting: SEO and Google Ads.
Related terms
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