PerfSell
2026
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Overview
PerfSell is an AI-powered analytics platform designed specifically for e-commerce performance tracking. It centralizes complex data into actionable insights to help sellers optimize their operations.
I was scouted via Malt.fr to transform a complete set of functional wireframes into a high-fidelity, production-ready interface. My mission was to refine the brand identity and build a scalable design system that could support a rapid, AI-driven development cycle.
Context
The project arrived with a clear vision: the user flows were already mapped out, and the wireframes were extensive. The unique advantage of this project was the client: the founders are also the primary users of the tool. This created an incredibly tight feedback loop where every design decision was immediately stress-tested against real-world utility.
The project was managed in weekly sprints. We began each week brainstorming specific features and ended with a review and validation session, ensuring the design stayed ahead of the fast-paced development.
The problem
While the functional foundation was solid, the initial wireframes lacked a cohesive visual language and the "premium" feel required for a professional analytics tool. The challenge wasn't just to "make it pretty," but to ensure that the density of e-commerce data didn't overwhelm the user.
Additionally, the development was being handled by the founders themselves using Grok AI. As a designer, this meant my handoff had to be exceptionally clean and structured the design system needed to be "bulletproof" so that AI-assisted coding could interpret the components and layouts without ambiguity.
Process
My process began with a deep dive into the objectives of each wireframe. After aligning on the UX optimizations, I initiated a "brand lifting" to modernize the visual identity.
Once the aesthetic direction was set, I built a comprehensive design system in Figma using variables and auto-layout. This ensured that as the founders added new AI-generated features, they had a consistent library of components to pull from, maintaining the integrity of the interface.
Key decisions
I focused heavily on visual consistency and information hierarchy. Because the tool handles large amounts of data, I insisted on refining the spacing and typography to reduce cognitive load.
One of the most rewarding aspects was the collaborative "founder-user" relationship. By having the end-user in the design chair, I could bypass typical "Discovery" guesswork and focus on high-speed execution and precision-engineered UX improvements that directly addressed their daily pain points.
Learnings and Why it Matters
PerfSell was a masterclass in efficiency, moving from wireframes to a fully operational, scalable design system in just one month.
It proved that when a designer works directly with the end-user, the result is a tool that is perfectly calibrated for its purpose. It also opened my eyes to the potential of AI in development; seeing the founders integrate my Figma designs so accurately using Grok AI was a testament to how a well-structured design system can bridge the gap between design and code—even without a traditional dev team.
A huge thanks to Arthur and Jeremy for their total trust. Working directly with founders who are also the end-users made this collaboration incredibly efficient and reminds me why I love building tools that solve real daily challenges.
Arthur Bracka | CEO - CAFOM Distribution
Un immense merci à Julien pour son accompagnement absolument parfait.
Disponible, bienveillant, ultra professionnel et toujours à l’écoute, il a su rendre les choses simples et fluides du début à la fin. On s’est sentis vraiment accompagnés, avec une vraie attention portée aux détails et une gentillesse rare.
C’est clairement le genre de personne qui fait toute la différence et qu’on recommande les yeux fermés.
Encore merci Julien pour tout, c’était un vrai plaisir !