Server-side tagging
Also called Server-side GTM, sGTM.
Moving tag execution out of the browser and onto a server you control. The page sends one request to your own endpoint, and that server decides what to forward to Google, Meta, TikTok and anywhere else.
Why it matters
It is the durable place to hold a click identifier and the first-party data that goes with it, and the one point in the chain where you can enrich an event before any platform sees it.
What goes wrong
The usual mistake is treating it as a tracking fix rather than an architecture change. It does not repair a form that never captured the identifier or a CRM field nobody mapped; it changes where the sending happens, so anything already missing upstream is still missing. It also becomes infrastructure somebody has to own, with a bill and an outage mode, which is a real cost worth naming before the migration rather than after.
How to check it on your own account
If events already reach every platform and your click identifiers are landing in the CRM, this is an improvement rather than a repair. Fix capture first, then consider moving it.
Next to this
- Google tag gateway for advertisersGoogle AdsNewServing Google's tag scripts and measurement requests through your own domain and first-party infrastructure, configured through a CDN, load balancer, web server or server-side tagging setup, rather than loading them from Google's domains.
- Signal lossThe umbrella term for measurement getting harder: third-party cookie restrictions, shortened browser storage lifetimes, consent refusals, and platform privacy changes, all reducing the share of activity that can be observed and attributed.
- Conversions APIMetaMeta's server-to-server route for sending events, used alongside or instead of the browser pixel.
- Enhanced conversions for leadsGoogle AdsMatching an offline conversion to an ad click using hashed first-party data, usually an email address, rather than a click identifier.
Where this comes up
The rest of this step
Measure this on your own data
The diagnostic reads a CRM export in your browser and reports your volume, your match rate and the spread between your leads against the thresholds in this glossary. Nothing is uploaded and no account is needed.