Canonical answers to the tracking questions everyone re-asks.
One page per question, no forum thread required: the answer in brief, why it actually happens, the fix - branched for the setups that matter - and how to verify it worked, not just that it "looks right."
What's the Actual Difference Between Google Tag Manager and Google Analytics?
One is a delivery mechanism. The other is a measurement platform. Confusing the two is the single most common analytics setup mistake.
Read Script PlacementWhere Should a Tracking Snippet Actually Go on the Page - Head, End of Body, Async or Defer?
The "just put it in the head" advice from a decade ago actively hurts your Core Web Vitals today. Here's the current answer, by setup.
Read Page SpeedHow Do I Stop Analytics and Tag-Manager Scripts From Hurting My Page Speed?
Every tag you add is a vote against your Core Web Vitals score. Here is how to keep the data without the tax.
Read CookiesHow Does a First-Party Analytics Cookie Actually Get Set and Scoped to My Domain?
"First-party" is a technical claim about which domain set the cookie - not a marketing term.
Read MechanicsMechanically, How Does a Web Analytics Tracker Actually Collect and Send a Hit?
Strip away the vendor SDK and every tracker does the same four things. Understanding the mechanism makes every future debugging session faster.
Read CSPWhat's the General CSP Pattern That Lets Tag Managers and Vendor Scripts Run Without unsafe-inline?
A strict Content Security Policy and a tag manager both want control of what runs on your page. Here is how to give them both what they need.
Read ArchitectureHow Do I Simplify or Re-Architect a GTM Setup That's Become Unmanageable on a Large Site?
Container sprawl doesn't happen all at once. It happens one "quick add" at a time, for years, until nobody can explain what half the tags are for.
ReadLooking for platform-specific fixes (GA4, GTM internals, Adobe, Amplitude) instead of architecture-level ones?