Server-side Google Tag Manager
Marc Alexander moves your tracking from the visitor's browser to a server on your own subdomain. The server passes each platform only what it needs, and only when the visitor has agreed. He designed server-side tagging at Halfords, from business case to cutover plan.
What you get.
£2,000 to £5,000, depending on how many platforms move and how much data needs transforming.
- Server container on Google Cloud or Stape, whichever suits your volumes
- A custom subdomain, so collection is first-party
- GA4 moved server-side, every event checked against the old setup
- Consent Mode v2 passed through, so each visitor's choice is honoured
- Meta Conversions API and Google Ads enhanced conversions, deduplicated
- Personal data hashed or removed before it reaches vendors
- Documentation of what runs where, and a handover session
How it works.
Review
Marc looks at your client-side container, tags and consent setup. If basic tracking is broken, that gets fixed first.
Plan
Which platforms move, what data each receives, where the server is hosted and what it will cost to run.
Build and test
The server setup runs alongside the existing one, so the numbers can be compared before anything is switched off.
Switch over
Client-side tags are retired once the server-side versions match. Then documentation and a walkthrough.
Straight answers.
Do we still need client-side GTM?
Yes. A client-side container still collects events in the browser, but it gets smaller: it sends one stream of data to your server instead of loading every vendor's script. Some tags still belong in the browser.
Is it a way round ad blockers or consent?
No, and it shouldn't be sold as one. If a visitor declines tracking, the server respects that just as the browser should. What server-side tagging does is make consented measurement more reliable and give you control over what each platform receives.
Is it compatible with UK GDPR?
Yes, when it's set up correctly, and it can make compliance easier: you decide exactly what leaves your infrastructure, you can strip or hash personal data first, and no third-party script runs on the page to collect things you didn't intend to share.
Will it work on our platform?
Most platforms can, including Shopify, WooCommerce, WordPress and custom builds. The requirements are a client-side GTM container and the ability to point a subdomain at the server. If something rules it out, that comes up before any build starts.
What does hosting cost?
The server container runs on Google Cloud or a specialist host such as Stape, billed monthly by the provider on top of the setup price. The cost depends on traffic, and Marc gives you an estimate for your volumes before you commit.
Can we do it ourselves?
If you have a developer who knows GTM well, yes: Google's documentation is decent. The risk is in the details. A misconfigured server container can drop or double-count key events, and ad platforms will happily optimise on the wrong numbers.
More detail: what server-side tagging is, and why businesses move to it
With client-side tagging, every vendor's script loads in the visitor's browser: GA4, Google Ads, the Meta pixel and whatever else has been added over the years. Each adds weight to the page and can read more of it than you might like.
With server-side GTM, the browser sends events to a server container on a subdomain of your site. The server forwards the right data to GA4, Google Ads, Meta and others. Because collection happens on your own domain, it counts as first-party, and you decide what each platform receives.
- Browser restrictions: browser restrictions on third-party cookies and tracking keep tightening. Safari limits cookies set by JavaScript to 7 days, so returning visitors look new. Cookies set by your own server last longer, although Safari adds conditions depending on how the server is hosted.
- Ad platforms ask for it: Meta's Conversions API and Google Ads enhanced conversions both work best with data sent from a server. Since Apple's App Tracking Transparency changes, Meta relies more on server-side signals to match conversions.
- Control over personal data: client-side tags can pick up anything on the page. Server-side, each vendor gets exactly the fields you choose.
- Lighter pages: fewer third-party scripts means less JavaScript to run and fewer things that can break mid-checkout. How much that helps depends on how many tags you run today.
More detail: is it right for you?
A good fit if:
- You spend meaningfully on paid media and attribution matters
- Meta or Google Ads under-report conversions compared with your own sales
- Revenue in GA4 doesn't match your payment processor
- Checkout involves several domains or payment gateways
- You work in a regulated sector and need tight control over what data leaves the site
Not yet if:
- Basic GA4 tracking isn't working yet
- Nobody on the team is comfortable with client-side GTM
- You don't run paid media and attribution isn't a pressing problem
- A monthly hosting bill on top of the setup cost doesn't make sense at your traffic
Other platforms such as TikTok can be added where needed. Want the raw data too? A GA4 to BigQuery connection is from £500. Ongoing monitoring is available on a monthly retainer, from £500 a month.
Where server-side fits in the wider setup: the best tracking architecture for a website.
If your client-side tracking is broken, fix that first: the GA4 mini audit is the sensible first step.
Last updated
Free tool
What does your site fire before consent?
Paste a page address. The tracking checker shows what a first-time visitor triggers before agreeing to anything, ranked by how much it matters.
Related work.
Ask about server-side GTM.
Tell Marc what you track today, which ad platforms you use and what's going wrong. He'll say whether server-side tagging is worth it for you yet. Project work is invoiced 50% at the start and 50% on completion.
Mini audit from £175.
Prefer to talk first? Choose "20-minute intro call" in the form.
Or email [email protected].