Google Tag Manager freelancer
Reliable data, in three steps.
I audit, implement and maintain tracking for e-commerce, SaaS and lead generation websites. For agencies, I work white-label.
- E-commerce
- SaaS
- Lead generation
- Agencies
My services
A journey in three steps
Start with a diagnosis, build a clean foundation, then keep it reliable over time. Each step can also be booked on its own.
Tracking audit
A full diagnosis of your setup to know what works, what breaks and where to start.
- Full review of your Google Tag Manager container: tags, triggers and variables
- GA4 data collection check: events, conversions and e-commerce data
- Ad pixels and conversions check (Google Ads, Meta, TikTok…)
Implementation
I design and deploy clean, documented tracking, from the browser to the server.
- Structured, documented tracking plan
- Organised Google Tag Manager web container with consistent naming
- GTM server-side hosted on Addingwell, Stape or Google Cloud
Ongoing support
I monitor your data collection and evolve your tracking at the pace of your website and campaigns.
- Data collection monitoring and anomaly alerts
- Fixes and improvements to your GTM setup
- Watch on browsers, Consent Mode and ad platforms
Agencies
Your white-label tracking expert
You run acquisition for your clients but tracking takes too much time or goes beyond your expertise? I work for your clients, under your brand, on audits, implementation or ongoing support.
- Deliverables in your branding
- I work with your teams and processes
- Audit, implementation and support, per project or ongoing
Process
How we work together
You get in touch
Through the form or by booking a discovery call right away.
Discovery call
We review your tracking, your tools and your business goals.
Proposal
I send you a clear proposal: scope, deliverables, timeline and quote.
Kick-off
You grant the required access and we start the project.
Proof
They trust me
« His technical expertise is impressive, but above all very well explained, which makes exchanges simple and efficient even for non-technical profiles. The tracking setup (GA4, GTM, events, conversions, consent, etc.) is carried out with great rigour and precision. »
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« I have worked with Lucas many times on various data collection and performance tracking issues. His technical expertise is impressive, but above all very well explained, which makes exchanges simple and efficient even for non-technical profiles. The tracking setup (GA4, GTM, events, conversions, consent, etc.) is carried out with great rigour and precision. Beyond his technical skills, I particularly appreciated his responsiveness, his teaching approach and his professionalism. He takes the time to understand the business stakes and always suggests relevant, tailored solutions. I highly recommend his services to any company that wants to improve its analytics tracking and data quality. »
« We brought Lucas in to update the tracking of our e-commerce site with a move to a server-side setup. Deadlines were met and the rollout was closely followed, in coordination with our developers, right up to the full check that our new tagging worked properly. »
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« We brought Lucas in to update the tracking of our e-commerce site with a move to a server-side setup, and the experience went very well from start to finish. Lucas explained technical topics with a lot of pedagogy, helping us understand these complex, specific subjects. Deadlines were met and the rollout was closely followed, in coordination with our developers (DataLayer update), right up to the full check that our new tagging worked properly. He also recommended key partners for our needs and started the conversations with them, which saved us precious time. Throughout the project he was very responsive, drove progress and was solution-oriented. We will work with him again without hesitation and recommend his services. »
« Lucas took charge of implementing server-side tracking via GTM for Google Analytics 4, migrating third parties, and circumventing Safari ITP limitations. Throughout the mission, Lucas demonstrated solid technical expertise, great rigor, and an impressive ability to adapt. »
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« I had the pleasure of collaborating with Lucas Rollin on a complex project for the Lafreto group, including managing the tracking of 5 websites, including Glisshop. Lucas took charge of implementing server-side tracking via GTM for Google Analytics 4, migrating third parties, and circumventing Safari ITP limitations. Throughout the mission, Lucas demonstrated solid technical expertise, great rigor, and an impressive ability to adapt to technical and structural challenges. His structured and proactive approach enabled the mission to be successfully completed. The client felt well supported, and I was able to trust his role. I highly recommend Lucas for any project requiring a tracking and analytics expert, and I would not hesitate to work with him again in the future! A little plus for his availability and responsiveness. »
Hugo HeitzData Marketing Manager @ Elevate · October 2024« Lucas assisted us in implementing server-side tracking with Addingwell as part of our migration to a Shopify+ site. Project management was smooth and transparent, which allowed us to meet fairly tight deadlines. »
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« Lucas assisted us in implementing server-side tracking with Addingwell as part of our migration to a Shopify+ site. Project management was smooth and transparent, which allowed us to meet fairly tight deadlines. Lucas fully understood the specifics of this migration compared to the existing system and provided us with all his expertise to implement the most efficient setup possible. Communication was very fluid and the project went very well. I will not hesitate to contact Lucas again for a future tracking project and I highly recommend him to my e-commerce colleagues who are undertaking a move to a server-side. »
Inès FlorentinyE-Commerce & Acquisition Manager, myBlend (Clarins Group) · October 2024« His support was simply impeccable: he took the time to train me, answer all my questions, and above all, he never let me go until I was completely independent! »
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« I had the chance to work with Lucas to set up all the server-side tracking, CMP management, and GTM configuration on several of my campaigns. His support was simply impeccable: he took the time to train me, answer all my questions, and above all, he never let me go until I was completely independent! It's rare to come across someone so professional, competent, and involved. Always available, educational, and ultra-reliable. If you're looking for a trusted expert for your technical and strategic tracking issues, you can go there with your eyes closed. I recommend him 200%! »
« Great experience with Lucas! In less than a week, he overhauled my entire tracking system across my three sites. He even went above and beyond by sending me an explanatory video at the end. I recommend him 100%. »
Case study
My Blend: +200% revenue growth
myBlend achieved +200% revenue growth in a single year.
Read the case study →
Case study
GTM Server-Side implementation project
+9% on purchasing events in Meta.
Read the case study →
Case study
French artist's shop needs reliable tracking
A French artist's label needs to make its tracking more reliable with a server-side configuration
Read the case study →About
Who am I?
My name is Lucas Rollin, founder of Data Marketing School. A computer engineer by training, I worked as a full-stack developer before going freelance. After some experience in media buying, I found my genius zone in tracking.

In 2023, after helping my first clients set up their Google Ads conversions and Google Analytics events, I launched the Data Marketing School blog: free, actionable tutorials that make tracking accessible to everyone.
Tools I use on client projects
Shopify
Wordpress
Prestashop
Didomi CMP
Axeptio CMP
OneTrust CMP
Cookiebot CMP
Javascript
Google Analytics
Matomo Analytics
Google Ads
Meta Ads
Tiktok Ads
Pinterest Ads
Snapchat Ads
LinkedIn Ads
GTM Web
GTM Server-Side
Addingwell
Stape
FAQ
Frequently asked questions
How much do your services cost?
Which service should I start with?
Do you work with international clients?
Do you work with agencies?
Which tools do you master?
Let's get started
Ready to make your data reliable?
Describe your project through the form or book a slot right away to talk it through.


