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─────── Case Study  ·  Marketing Agency  ·  Server-Side Tracking

From 1.7 to 8.0 ROAS in the first 30 days.

A marketing agency's client was losing 25% of purchase events to ad blockers. Meta and Google campaigns were optimising on incomplete data. We fixed the tracking. The results followed.

3.8× Final ROAS
up from 1.7
+22% Attributed conversions
recovered
+15% Budget increase
unlocked
01 — The Problem

Their data looked fine. Their decisions were not.

The agency came to us with a problem they couldn't resolve internally: platform numbers and back-end numbers told different stories. Meta reported a 3.0 ROAS. The actual back-end consistently indicated 4.0. The gap had been there for months.

They weren't missing a few events here and there. They were systematically underreporting to ad platforms, meaning every automated bidding decision was working from a distorted picture of what was actually driving revenue.

  • ×
    25% of purchase events lost to ad blockers, concentrated in the highest-value customer segment
  • ×
    Meta and Google optimising on artificially low conversion signals
  • ×
    No Meta Conversions API in place; relying entirely on the browser-based pixel
  • ×
    Budget decisions constrained by fear of scaling on unreliable data
02 — What We Did

A server-side setup built around their data pipeline, not a template.

We audited the full tracking architecture first. Once we understood exactly where events were dropping, we built a server-side GTM implementation designed around their specific stack and campaign structure.

  • GTM Audit Mapped every tag, trigger, and variable. Identified duplicate events, missing data layer pushes, and the precise points where ad blocker interference was occurring.
  • Server-Side GTM Container Deployed a server-side container on a first-party subdomain. Events now route through infrastructure the client controls, bypassing browser-level blocking entirely.
  • Meta Conversions API + Deduplication Implemented Meta CAPI alongside the browser pixel with proper event deduplication. Both signals reach Meta; no double-counting, no gaps.
  • Clean Data Layer Architecture Rebuilt the data layer to carry consistent, complete event payloads. GA4, Google Ads, and Meta now receive the same source of truth.
03 — The Results

Better data. Better decisions. Better returns.

Within 30 days of go-live, the improvement was measurable across every platform. The campaigns stayed the same. The data quality changed.

3.8× ROAS up from 3.0. Ad platforms now optimising on complete, accurate purchase signals.
+22% Attributed conversions recovered in Meta Ads within the first month.
+15% Budget increase approved with confidence, backed by reliable attribution data.
0% Events lost to ad blockers. Server-side routing removed the dependency on browser execution entirely.
The gap between the reported 3.0 and actual 4.0 ROAS had been there for months. Once the tracking reflected reality, the platform algorithms had what they needed. The improvement happened fast.
What clients say
" Expertly helped by Jerry. Fast, critical, and a true specialist. Our tracking is back on point. It's great to finally have a clear picture of where clients come from and to make decisions based on leads and data.
LZ
Linda Zwanenburg Trustpilot · ★★★★★
" I'd been trying to get the right GTM setup for ages. After a few workshops with Jerry, everything started clicking into place. No nonsense, just someone who knows what he's talking about and actually moves you forward.
MA
Mark Trustpilot · ★★★★★

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