Case Study

D2C Fashion Brand sGTM Migration

How we recovered 147% more tracked conversions and cut CPA by 31% in 3 weeks.

Work / D2C Fashion Brand

Industry
Fashion & Apparel
Timeline
3 weeks
Services
Server-Side Tracking, Analytics
Year
2025
The challenge

A mid-size D2C fashion brand with €3M annual ad spend across Meta, Google, and TikTok was losing 40%+ of conversion data due to ITP, ad blockers, and iOS privacy changes. Their Meta ROAS appeared at 1.8x — below break-even. The marketing team was about to cut Meta budget by 50%. Attribution was broken, remarketing audiences were shrinking weekly, and the team had zero visibility into which campaigns actually drove profit.

Our approach

We audited their existing GTM setup and discovered 23 broken tags and 6 redundant triggers creating data duplication and blindspots. We designed a server-side architecture with sGTM on Stape.io, implementing Meta CAPI, Google Ads Enhanced Conversions, and TikTok Events API. We set up FPID cookies for 180-day persistence, configured event deduplication to prevent double-counting, and built Consent Mode v2 for GDPR compliance. Full QA with real-time validation dashboard ensured zero data loss during migration.

+147%
Tracked conversions recovered
-31%
Reduction in CPA
3.4x
Actual Meta ROAS (was 1.8x)
91%
FPID cookie coverage

"We were about to cut our Meta budget in half. After reiterweb's sGTM implementation, we discovered our actual ROAS was nearly double what we thought. They saved our marketing strategy."

— Head of Digital, D2C Fashion Brand

Tech Stack
Google Tag Manager
Stape.io
Meta Conversions API
Google Ads
TikTok Events API
BigQuery

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