Tracking Agency
You can't improve what you don't measure.
Clean, reliable, and actionable tracking to drive your decisions, optimize your conversions, and align marketing, sales, and product with a single source of truth.
Why implement reliable tracking?
Better attribution = Better decision-making
Reliable server-side tracking gives you +15 to +30% more correctly attributed conversions, without the losses due to ad blockers and cookies. You finally see which channels are truly profitable.
Lower CPA / CAC
Reliable signals allow Google & Meta algorithms to optimize for the right events. The result: faster budget reallocation to truly performing campaigns, and a -10 to -25% CPA observed on high-volume accounts.
More stable and scalable ROAS
Clean data means algorithms learn better. You gain stability during budget increases, and your mature campaigns achieve +10 to +40% ROAS.
These companies' marketing teams trust us

"Most agencies make a great first impression and sell you the dream in those early conversations, but that illusion fades fast once the contract is signed. With Gemeos, it’s different. Gemeos are professional and genuinely committed to doing things right and fast. I really recommend them. And this is the first time I’ve ever recommended an agency.
Quentin MayetVP Marketing @Paradox 
"We sent the Figma files. We got the website back. Pixel-perfect, without a single unnecessary back-and-forth. The whole team noticed."
Typhaine RoyerCEO @Join Stories 
"We worked with Gemeos for several months on the redesign of our site and the launch of our new Taalent.ai offering in the U.S. market. The team was able to combine strategic vision, high-quality execution, and great responsiveness throughout the project. An effective collaboration that I’d recommend without hesitation."
Alexandre DuffautCEO @Noota 
Thanks to the whole team, always going the extra mile to push the boundaries!
Florent DarraultCMO @Cureety 
We entrusted Gemeos with a full website redesign and migration, and everything went incredibly smoothly. What stood out most to us was the quality of the art direction: a truly premium, cohesive visual direction, with a clear visual identity and highly polished choices throughout, typography, colors, iconography, pacing, hierarchy, and more. You can tell they have great taste, and above all, a real eye for detail on every screen. On top of that, the team is incredibly responsive and very experienced: they know both design and the technical side inside out. I’d recommend them without hesitation.
David BERNARDCEO & Founder @AssessFirst - Your logo

“Gemeos delivered a showcase site that met all our requirements while working to quite tight deadlines. Their methodology was efficient, and they remained available, attentive, and highly responsive throughout the project. They are a complementary and very skilled duo. Kudos to them!”
Thibaud BertrandHead of Marketing @Side
Services Offered by Our Tracking Agency
You're Flying Blind
(We'll Turn on the Lights)
No Blind Spots
We don't measure what's easy to measure. We measure what enables you to make better decisions
Single source of truth
GA4, CRM, advertising platforms: all your data speaks the same language. No more conflicting numbers depending on the tool, no more debates about which source to trust.
Better attribution
You know exactly which channel and campaign generates your customers. Not your sessions, your customers.
Scalable tracking
Every event is documented. When you change tools or providers, your infrastructure remains consistent.
Server-side tracking
We implement server-side tracking to bypass browser limitations: ad blockers, ITP, cookie restrictions. You capture data that others lose.
The goal of tracking
custom
We entrusted Gemeos with a full website redesign and migration, and everything went incredibly smoothly. What stood out most to us was the quality of the art direction: a truly premium, cohesive visual direction, with a clear visual identity and highly polished choices throughout, typography, colors, iconography, pacing, hierarchy, and more. You can tell they have great taste, and above all, a real eye for detail on every screen. On top of that, the team is incredibly responsive and very experienced: they know both design and the technical side inside out. I’d recommend them without hesitation.
David BERNARDCEO & Founder @AssessFirstEfficiency, structure, and performance. Gemeos managed to translate Avnear’s identity into a website that exceeded our expectations. Client feedback has been unanimous. The team showed remarkable agility in adapting to our requests and our high standards. A trusted partner we’d recommend without hesitation. Our site is a masterclass in building trust.
Charley ArodFounding Partner. Asset & Risk Management @Avnear"Gemeos worked on the Webflow integration as part of our website redesign, with the goal of giving our Growth team back control over landing page creation and improving web performance and SEO. I highly recommend Sandro for his availability, responsiveness, teaching approach, and, above all, his understanding of our business needs."
Florian CorteelSEO Manager @Finary"I'll be honest: we had nothing. A website thrown together in 2023, no identity, zero visibility on Google. We were selling wealth structuring with a website that proved the exact opposite. Today, it's coherent. It took time, but it's coherent."
Really great working with you, you get up to speed really fast, and the process is frictionless 🔥
Kévin Moënne-LoccozVP of Product & Design @Lemlist“We worked with Gemeos in the summer of 2024 to redesign Modjo’s marketing site and better reflect the brand’s new positioning. The collaboration was incredibly efficient, the agency was highly responsive and adapted to every unexpected challenge. With limited resources on our side, right in the middle of summer, we launched the new site in just six weeks. Site visit engagement increased by 58%!”
Thomas BeylotVP Product @ModjoOur methodology for implementing your tracking
Cut what doesn't work, scale the rest
We instrument your site to measure what truly matters: the actions, sources, and journeys that generate customers.

Existing Setup Audit
We start by evaluating what you're already measuring: GA4 configuration, existing events, GTM tags, advertising pixels, CRM integrations. We identify blind spots, missing data, and incorrect measurements that are skewing your decisions today.

Tracking Plan
Together, we define what needs to be measured. Each event is named, documented, and linked to a specific business objective. You'll have a clear reference.

GTM Implementation
We configure or restructure your Google Tag Manager container: tags, triggers, variables, data layer. Each event is cleanly implemented, tested in preview mode, and validated before publication. No duplicate tags, no data overwrites.

UTM Tracking & Attribution
We implement a consistent UTM convention across all your channels: paid campaigns, emails, social media, partners. We configure parameter persistence via sessionStorage to ensure no source is lost between the first click and conversion. Every lead is attributed to the correct source.

CRM & Marketing Tool Connections
We connect your tracking to your stack: sending conversions to Google Ads, Meta, LinkedIn, transmitting data to your CRM, integrating with your email marketing tool. Data doesn't just stay in GA4, it fuels your decisions and advertising algorithms.

Existing Setup Audit
We start by evaluating what you're already measuring: GA4 configuration, existing events, GTM tags, advertising pixels, CRM integrations. We identify blind spots, missing data, and incorrect measurements that are skewing your decisions today.

Tracking Plan
Together, we define what needs to be measured. Each event is named, documented, and linked to a specific business objective. You'll have a clear reference.

GTM Implementation
We configure or restructure your Google Tag Manager container: tags, triggers, variables, data layer. Each event is cleanly implemented, tested in preview mode, and validated before publication. No duplicate tags, no data overwrites.

UTM Tracking & Attribution
We implement a consistent UTM convention across all your channels: paid campaigns, emails, social media, partners. We configure parameter persistence via sessionStorage to ensure no source is lost between the first click and conversion. Every lead is attributed to the correct source.

CRM & Marketing Tool Connections
We connect your tracking to your stack: sending conversions to Google Ads, Meta, LinkedIn, transmitting data to your CRM, integrating with your email marketing tool. Data doesn't just stay in GA4, it fuels your decisions and advertising algorithms.
+250 companies supported
What our clients say about Gemeos
4.9/5· 97 reviews
"Most agencies make a great first impression and sell you the dream in those early conversations, but that illusion fades fast once the contract is signed. With Gemeos, it’s different. Gemeos are professional and genuinely committed to doing things right and fast. I really recommend them. And this is the first time I’ve ever recommended an agency.
Quentin MayetVP Marketing @Paradox“We worked with Gemeos in the summer of 2024 to redesign Modjo’s marketing site and better reflect the brand’s new positioning. The collaboration was incredibly efficient, the agency was highly responsive and adapted to every unexpected challenge. With limited resources on our side, right in the middle of summer, we launched the new site in just six weeks. Site visit engagement increased by 58%!”
Thomas BeylotVP Product @Modjo“Gemeos are the perfect experts to take over your website from A to Z. Beyond being highly skilled, they were proactive and came up with great ideas throughout the project, a real plus! Thanks for this fantastic Openeat website redesign ;)”
Martin CatineauHead of Market @OpeneatReally great working with you, you get up to speed really fast, and the process is frictionless 🔥
Kévin Moënne-LoccozVP of Product & Design @Lemlist“Sandro and his team are incredibly efficient and really attentive. They have a great grasp of their clients’ SEO challenges and always come up with the right solutions. Highly recommend”
Jules RatierCEO @Koncile“Gemeos delivered a showcase site that met all our requirements while working to quite tight deadlines. Their methodology was efficient, and they remained available, attentive, and highly responsive throughout the project. They are a complementary and very skilled duo. Kudos to them!”
Thibaud BertrandHead of Marketing @Side“Great Webflow agency. Available, attentive, and responsive. We brought them in to redesign our Nuant.com website, providing the Figma mockups. We’re very happy with the result, and their Webflow expertise is a real asset.”
Leo CarliProduct Marketing Manager @Nuant"We worked with Gemeos for several months on the redesign of our site and the launch of our new Taalent.ai offering in the U.S. market. The team was able to combine strategic vision, high-quality execution, and great responsiveness throughout the project. An effective collaboration that I’d recommend without hesitation."
Alexandre DuffautCEO @NootaEfficiency, structure, and performance. Gemeos managed to translate Avnear’s identity into a website that exceeded our expectations. Client feedback has been unanimous. The team showed remarkable agility in adapting to our requests and our high standards. A trusted partner we’d recommend without hesitation. Our site is a masterclass in building trust.
Charley ArodFounding Partner. Asset & Risk Management @Avnear"Gemeos worked on the Webflow integration as part of our website redesign, with the goal of giving our Growth team back control over landing page creation and improving web performance and SEO. I highly recommend Sandro for his availability, responsiveness, teaching approach, and, above all, his understanding of our business needs."
Florian CorteelSEO Manager @FinaryThanks to the whole team, always going the extra mile to push the boundaries!
Florent DarraultCMO @CureetyWe entrusted Gemeos with a full website redesign and migration, and everything went incredibly smoothly. What stood out most to us was the quality of the art direction: a truly premium, cohesive visual direction, with a clear visual identity and highly polished choices throughout, typography, colors, iconography, pacing, hierarchy, and more. You can tell they have great taste, and above all, a real eye for detail on every screen. On top of that, the team is incredibly responsive and very experienced: they know both design and the technical side inside out. I’d recommend them without hesitation.
David BERNARDCEO & Founder @AssessFirst"Sacha & Sandro worked on the redesign and migration of our website with a few clear goals: create a unique, differentiated visual identity, clarify our message and value proposition, smooth out the customer journey, and ultimately generate more business opportunities. We’re very happy with the result, and the numbers speak for themselves. Sacha & Sandro are skilled, committed, conscientious, passionate, and they see things through to the end. I highly recommend them!”
Idir AIT SI AMERCEO @TracktorWhat the FAQ?
What is a tracking agency?
A tracking agency implements and structures the measurement system for your digital presence: what events are tracked on your site, how data is collected, sent to the right tools, and utilized to make marketing decisions. Without reliable tracking, you're flying blind: you spend ad budgets without knowing what converts, you optimize pages without real data, you make decisions based on erroneous figures.
At Gemeos, tracking is integrated into every web and CRO project. A website delivered without a configured tracking plan is a site that cannot be optimized.
Server-side tracking: why adopt it?
Client-side tracking (via the browser) has been losing reliability for several years due to adblockers, browser restrictions (ITP on Safari), and the disappearance of third-party cookies. Server-side tracking bypasses these limitations by sending data directly from your server to analytics and advertising platforms, without going through the user's browser.
| Client-side tracking | Server-side tracking | |
|---|---|---|
| Data reliability | Degraded by ad blockers and ITP | High, independent of the browser |
| Impact of ad blockers | Up to 30% of data lost | Almost none |
| GDPR compliance | Harder to control | Better control over the data sent |
| Site performance | Third-party scripts that slow down loading | Fewer scripts in the browser |
| Implementation complexity | Low | More technical, requires expertise |
For businesses investing in digital advertising (Meta Ads, Google Ads), server-side tracking has become essential to maintain the quality of the signal sent to targeting algorithms. A degraded signal means an algorithm that optimizes poorly, leading to an increased cost per acquisition.
How to choose a tracking agency?
The main criterion: does the agency start by auditing your existing implementation before proposing solutions? A good tracking agency doesn't sell technology; it solves a measurement problem. It should be able to explain precisely what data you are currently losing, why, and how to recover it.
Also check their proficiency with the tools that make up your stack: GA4, GTM, Meta CAPI, Google Ads Enhanced Conversions, and CMPs (Consent Management Platforms) for GDPR compliance.
| Criterion | Good agency | Red flag |
|---|---|---|
| Starting point | Audit of the existing setup before any recommendation | Proposes a solution without seeing your setup |
| Transparency | Explains what is lost and why | Technical jargon without clear explanation |
| Documentation | Tracking plan delivered and maintained | Implementation without documentation |
| Compliance | Builds GDPR in from the start | Never mentions compliance |
How much does a tracking service cost?
The cost of a tracking service depends on the complexity of the setup: number of events to track, tools to connect, and whether server-side tracking is needed.
| Type of service | Indicative range | What's included |
|---|---|---|
| Audit of existing tracking | €800 to €2,000 | Setup analysis, list of errors, recommendations |
| GA4 + GTM setup | €1,500 to €3,500 | Full configuration, key events, conversions |
| Full ads tracking (Meta + Google) | €2,000 to €5,000 | Pixels, conversions, Enhanced Conversions or CAPI |
| Server-side tracking | €3,000 to €8,000 | Server-side setup, platform connections, tests |
| Complete tracking plan | Included in the services above | Documentation of every tracked event |
Why use Google Tag Manager?
Google Tag Manager (GTM) is a tag management system that centralizes all your site's tracking scripts in one place, without requiring code modifications for each new addition. Without GTM, every new pixel, analytics script, or remarketing script requires developer intervention. With GTM, it's manageable directly from an interface, with precise triggering rules.
| GTM advantage | What it changes in practice |
|---|---|
| Centralized scripts | A single tool to manage every pixel and script |
| Independent marketing teams | Add tags without a developer |
| Precise triggers | Conditional tracking by page, action or scroll |
| Versioning | Change history, rollback possible |
| Built-in debugging | Preview mode to test before publishing |
On Webflow, GTM is integrated by adding the snippet to the project's <head> section. This is the first thing we configure on every new project, even before connecting GA4 or ad pixels.
Is tracking mandatory for digital marketing?
Not legally, but practically, yes. Without tracking, you cannot measure the return on investment of your campaigns, identify converting pages, optimize your conversion funnels, or properly feed advertising algorithms. You can spend marketing budgets without tracking, but you'll never know what's working.
More specifically: without configured tracking, Meta and Google Ads algorithms receive an incomplete signal about your conversions. They optimize poorly, target less effectively, and your cost per acquisition mechanically increases.
| Without tracking | With well-configured tracking |
|---|---|
| Impossible to measure ROI per channel | Precise attribution by source and campaign |
| Ad algorithms poorly fed | Strong conversion signal, optimized targeting |
| Decisions based on gut feeling | Decisions based on real data |
| CRO optimization impossible | Data-driven A/B tests and optimizations |
How to be GDPR compliant?
GDPR compliance for tracking is based on a simple principle: you cannot place tracking cookies without the user's explicit consent. In practice, this involves three elements: a correctly configured CMP (Consent Management Platform), conditional tracking that only activates after consent, and documentation of your data processing.
| Compliance element | What it involves | Common tools |
|---|---|---|
| Consent banner (CMP) | Collect and store consent before any tracking | Axeptio, Cookiebot, Didomi |
| Conditional tracking | Scripts only load after consent | GTM + consent triggers |
| Privacy policy | Document the data collected and how it's used | Dedicated page on the site |
| Record of processing | Keep the list of processed data up to date | Mandatory internal document |
A frequently overlooked point: a poorly configured CMP can block your tracking for 60 to 80% of visitors, even those who have consented. The technical configuration of the CMP in conjunction with GTM is as important as the banner itself. This is an issue we systematically address in our projects to avoid losing legitimate conversion data.
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