GTM Implementation & Custom Builds

A tracking setup built once, properly, that grows with your business, not one that needs ripping up every six months.

If you’re launching from scratch, migrating off another tag manager, or moving from a basic GA4 setup to something that actually supports the platforms you’re spending on, you need more than the GTM template. You need a setup designed around your business - your dataLayer, your products, your ad platforms, your consent obligations.

I build full GTM containers from the ground up, or rebuild existing ones where they’re past the point of cleanup.

What’s included.

DataLayer design

The foundation of everything else. A clean, consistent dataLayer that:

  • Captures what your tracking actually needs — products, transactions, users, custom events

  • Works across GA4, Meta, TikTok, Google Ads, Microsoft and any other platform you add later

  • Survives platform changes without needing to be rebuilt

  • Is documented so your dev team can extend it without breaking it

Custom Javascript

Where the GTM out-of-the-box isn’t enough - custom JS to:

  • Extract product IDs in the exact format each ad platform wants

  • Handle deduplication between Pixel and CAPI / Events API

  • Normalise inconsistent data from older platforms and legacy code

  • Hash customer data for Enhanced Conversions and CAPI Advanced Matching

GA4 ecommerce or lead tracking

  • Full GA4 ecommerce coverage (view_item through purchase) or lead-gen events (form submissions, calls, downloads, demos)

  • Custom dimensions and metrics tied to your reporting needs

  • Conversion configuration and key events

  • Cross-domain tracking where required

  • BigQuery export — set up properly so the raw data is usable

Consent configuration

  • Consent Mode v2 integration with your CMP - Cookiebot, OneTrust, CookieYes, or other

  • Per-tag consent requirements, properly gated

  • Built-in consent checks for any tag that needs them

  • A setup that’s compliant by default, not by accident

Mutli-platform conversion tracking

  • Meta Pixel base + Conversions API, deduplicated so they don’t double-count

  • TikTok Pixel and Events API

  • Google Ads conversions with Enhanced Conversions

  • Microsoft and Bing UET

  • LinkedIn Insight Tag, Pinterest Tag, others as needed

Testing & validation

  • Tag firing tested in Preview mode and on the live site

  • Deduplication verified across Pixel / CAPI / Events API pairs

  • Consent behaviour tested in every consent state — granted, denied, partial, undecided

  • Real purchase or lead walkthroughs from end to end

Documentation

The bit that usually gets skipped - and the bit that matters most six months from now. You get:

  • A full container map - every tag, trigger, variable and what they do

  • A dataLayer reference your dev team can build against

  • Per-tag firing logic and consent requirements

  • Known issues, outstanding items and recommended next steps

Inquire

How it works.

1. Scope & access

We start with a conversation about your platforms, your stack, your reporting needs, and the timeline. I’ll come back with a clear scope and a fixed fee.

2. Build

I build the container, write the custom JS, configure the platforms and integrate consent. You get progress updates and the chance to review before anything goes live.

3. Validate

Nothing goes live without proper testing. Deduplication checks, consent state checks, end-to-end purchase or lead walkthroughs, network request inspection.

4. Document & handover

Full documentation and a walkthrough for your team or agency. I’m available for follow-up questions after handover — no black boxes, no disappearing acts.

This is for you if...

  • You’re launching a new site and want tracking built in properly from day one

  • You’ve outgrown a basic GTM template setup

  • You’re scaling ad spend across multiple platforms and need cleaner data

  • You’re migrating off Universal Analytics, another tag manager or a CDP

  • Your dev team has a tracking setup that’s hard to maintain

  • You want a setup that doesn’t need a specialist on call every time you add a new product or button

Recent builds.

  • A full GTM container for a proprietary trading platform - GA4 ecommerce, the full Meta Pixel suite (PageView through Purchase), Microsoft Bing UET, deduplication logic and consent

  • A water irrigation ecommerce site - full GTM build with ecommerce tracking, multi-platform conversions and dev handover documentation

  • A UK ecommerce brand - Meta + Bing UET + GA4 stack with proprietary dedup logic, purchase data now reconciling to the order management system within 1%

Let’s build it properly.

Whether you’re starting from scratch or rebuilding something that’s outgrown its original setup, get in touch and we’ll talk through what’s needed.