Custom development
Interaction for Conversion
Simulators, calculators, multi-step forms, lead magnets. We develop custom tools to turn your site into a lead-generating machine.
3 reasons to add tools to your website
01
You turn your visitors into qualified leads
Simulators, calculators, multi-step forms… These tools are designed to engage visitors at the right moment and naturally lead them to contact you.
02
You capture demand that your competitors let slip away
A well-designed lead magnet means prospects willingly provide their contact information in exchange for value. You build a qualified database, entirely on your own.
03
You increase the conversion rate
Price simulators, ROI calculators, smart forms… Each tool is designed to reduce friction and accelerate the purchasing decision. Your prospect will no longer have a reason to hesitate.
These companies' marketing teams trust us
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Mathieu M
CMO
examples of tools we've built
Tools that turn your visitors into leads
Investment simulators
Help your visitors picture themselves in seconds. The more they interact, the more qualified they become, and the more they convert.
Custom charts
See your product's value at a glance. Less effort to understand means more conversions.
Calculators
Provide a personalized result in exchange for an action. A simple way to convert cold traffic into opportunities.
They trusted gemeos
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 BERNARD
CEO & Founder @AssessFirst
Efficiency, 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 Arod
Founding Partner. Asset & Risk Management @Avnear
A great experience with Gemeos on our website redesign. The team was responsive, attentive, and proactive from start to finish. The result perfectly reflects the image we wanted to convey.
Loïc Calvy
Co-founder @Bloomays
Thanks to the whole team, always going the extra mile to push the boundaries!
Florent Darrault
CMO @Cureety
Adaptability, Speed, Great communication, Specialist(s), Efficiency, Good vibes, Professionalism, Competitive pricing, Agility, Strong support, Analytical skills, Cutting-edge, Seriousness, Friendly, Responsiveness, Flexibility, Reliability, Expertise, Attentive, Creativity
Hugo Bouchillou
CEO @Cycle Events
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 Corteel
SEO Manager @Finary
Our Methodology
Tools that convert. Without an in-house tech team.
Simulators, smart forms, calculators,
now directly accessible within your Webflow.
Discovery & Recommendation
Discovery & Recommendation
We start by understanding your offer, your target audience, and your conversion funnel. Based on this, we propose a selection of relevant tools for your context: simulator, configurator, ROI calculator, smart form, qualification quiz...
Solution Selection
Solution Selection
Depending on your needs, we choose the right approach: native Webflow component, custom script, external library, or API connection. The goal is always the same: the most robust, maintainable solution, least dependent on a fragile third party.
Prototype & Business Logic
Prototype & Business Logic
We build the tool's logic: calculations, conditions, display rules, and state management. You validate the behavior before we proceed with integration.
Integration
Integration
The tool is integrated into your site with the same high standards as the rest: responsive, consistent with your brand guidelines, and fast-loading. Interactive charts, sliders, conditional fields: every interaction is meticulously crafted.
Connections & Data Transmission
Connections & Data Transmission
Your tool doesn't operate in isolation. We connect the outputs to your CRM, email marketing tool, database, or sales team via Zapier, Make, or direct API. Every lead, every simulation, every submitted form is tracked and actionable.
Testing & Delivery
Testing & Delivery
We test all scenarios: edge cases, input errors, mobile behavior, and speed. You receive the documented tool, with instructions to modify or extend it yourself if needed.
Discovery & Recommendations
We start by understanding your offer, your target audience, and your conversion funnel. Based on this, we propose a selection of relevant tools for your context: simulator, configurator, ROI calculator, smart form, qualification quiz...
Solution Selection
Depending on your needs, we choose the right approach: native Webflow component, custom script, external library, or API connection. The goal is always the same: the most robust, most maintainable solution, least dependent on a fragile third party.
Prototype & Business Logic
We build the tool's logic: calculations, conditions, display rules, and state management. You validate the behavior before we move to integration.
Integration
The tool is integrated into your site with the same high standards as the rest: responsive, consistent with your brand guidelines, fast-loading. Interactive curves, sliders, conditional fields: every interaction is meticulously crafted.
Connections & Data Transmission
Your tool doesn't live in isolation. We connect the outputs to your CRM, email marketing tool, database, or sales team via Zapier, Make, or direct API. Every lead, every simulation, every submitted form is tracked and actionable.
Testing & Delivery
We test all scenarios: edge cases, input errors, mobile behavior, speed. You receive the documented tool, with instructions to modify or extend it yourself if needed.
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 Mayet
VP 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 Beylot
VP 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 Catineau
Head of Market @Openeat
Really great working with you — you get up to speed really fast, and the process is frictionless 🔥
Kévin Moënne-Loccoz
VP 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 Ratier
CEO @Koncile
Gemeos delivered a showcase website that met our standards, while still working within a pretty tight timeline. Their process was efficient, and they were available, attentive, and very responsive throughout the project. They’re a highly complementary and very capable duo. Highly recommend!
Thibaud Bertrand
Head 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 Carli
Product 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 Duffaut
CEO @Noota
Efficiency, 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 Arod
Founding 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 Corteel
SEO Manager @Finary
Thanks to the whole team, always going the extra mile to push the boundaries!
Florent Darrault
CMO @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 BERNARD
CEO & 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 AMER
CEO @Tracktor
WhattheFAQ?
What is a custom tool for a website?
A custom tool is an interactive feature developed specifically for your website, designed to engage visitors and convert them into qualified leads. Unlike a standard contact form, a custom tool provides immediate value to the user: a personalized result, an estimate, a diagnosis, or a score. It's this value exchange that dramatically boosts conversion rates.
The most common custom tools: ROI calculators, price calculators, multi-step forms, qualification quizzes, interactive lead magnets, product configurators.
What types of custom tools do you offer?
At Gemeos, we develop four main categories of tools, all directly integrable into Webflow.
We have developed this type of tool for Moment Lab (gamified slot machine for lead capture) and Homunity (real estate investment simulator). In both cases, the engagement rate of pages equipped with these tools was significantly higher than pages without interactive tools.
How much does custom tool development cost?
The price depends on the complexity of the business logic, the design level, and the required integrations. A well-designed multi-step form is less complex to develop than a financial simulator with dynamic calculations and multiple scenarios.
These ranges include design, Webflow development, and basic CRM integration. Price variations are mainly due to the complexity of conditional logic and the number of result scenarios to manage.
Can a custom tool integrate with my CRM?
Yes, it's even essential. A custom tool without CRM integration generates data that remains on the site without feeding your sales pipeline. Every lead captured by the tool must arrive in your CRM with its qualification data: quiz answers, simulator parameters, score obtained.
We also systematically configure UTM tracking on submissions: every lead entering the CRM is tagged with its source, medium, and campaign. You know exactly which channel generated which lead via which tool.
What's the difference between a classic lead magnet and an interactive tool?
A classic lead magnet (ebook, PDF guide, checklist) exchanges content for an email. The problem: perceived value is increasingly low, conversion rates are eroding, and the lead provides no information about their actual needs.
An interactive tool generates personalized value in real-time: a result specific to the visitor's situation. This mechanism yields significantly higher conversion rates and infinitely better-qualified leads, because the answers provided during the journey precisely reveal the prospect's context and maturity level.
Which sectors benefit most from custom tools?
All sectors where the purchasing decision involves personal variables benefit massively from interactive tools. The more difficult it is to quantify the value proposition without context, the more a simulator or calculator makes a difference.
This is exactly the positioning we're developing at Gemeos in the Finance sector: investment simulators for wealth managers (CGP) and family offices, yield calculators for fintech platforms, and qualification tools for private wealth management firms.
Can a tool be updated after its delivery?
Yes, and it's even part of our approach. A custom tool behaves like a product: it optimizes itself based on usage data. The first few weeks after launch often reveal friction points in the user journey or result scenarios that need refinement.
We systematically recommend an optimization cycle 4 to 6 weeks after launch: analysis of completion rates per step, identification of abandonment points, UX adjustments, and calculation logic if necessary. This cycle is included in our custom tool projects, or available on retainer if you desire continuous optimization.
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