Guillaume Caillet Senior Product Designer France
Over the last 7 years, I've contributed to the design and improvement of B2B SaaS products, alongside teams at Oplit (industrial schedulers), PrestaShop (300k+ merchants), Airbus and SNCF. I've led design systems, run audits, and shipped infrastructure that teams build on.
What I'm looking for: high-stakes products where design co-pilots strategy, not a service function.
I came to design without really noticing it.. first through the games I played, then something deeper that stuck: a curiosity for graphic systems and the drive to build the things that had gradually fascinated me.
Senior Product Designer at Oplit, a B2B SaaS platform for industrial scheduling. I design for planners and shop-floor operators in luxury watchmaking, aerospace, and precision engineering. Expert users, direct operational impact. I took over and deployed Oplit's design system as a structural element of the organization, aligning design, engineering, and product around a shared language.
What interests me: SaaS environments where design shapes how organizations work. A decision framework that holds, a component system that speeds up the team, research that redirects a roadmap. I'm looking for roles where design co-pilots product strategy.
+74% active users (430 → 747) and key features now running on customers' production lines.
Oplit builds production planning software for industrial manufacturers in aerospace, luxury and automotive. I own design on the product: continuous discovery with customers and prospects, strategic features shipped with product and engineering, and the design system I rebuilt (44 components, structured for AI-assisted workflows) which made design execution 30 to 50% faster.
Product Designer & Design System Lead (2024)
Progressively structures and deploys the research system across PrestaShop. Responsible for structuring and making the tools, templates, and user data operationally available so product teams can access them quickly and efficiently. The aim is to provide efficient access to user search when designing PrestaShop products for our 300k+ merchants.
Also working on structuring the Design System to make it robust, flexible and scalable. Proposing areas for development, structuring the team around the project and giving visibility to what we're doing.
Design System contributor (2023)
Involved in structuring and implementing the PrestaShop Design System. Working on the monitoring, implementation, and use of components and design tokens by everyone who uses the design system, as well as the components designed by the Product Designers.
Product Designer (2022)
Within the Customer Platform team, working on the design and improvement of the user experience through the user account and, more generally, the login experience.
In charge of UX at Beapp, working mainly with the UI designer and in contact with all the people involved in the various customer projects (PO, Business, Tech).
Designing experiences for different types of clients in the healthcare, automotive, food, institutional, and other sectors. Running creativity, immersion, and co-creation workshops. In charge of user research and testing.
Work as a UX consultant for companies looking to improve their user experience.
Joined the team of UX/UI designers (UXiD) as part of a process to digitalize the Airbus Group. The team designs and redesigns processes as well as business applications and HMIs, putting people back at the heart of their design.
Responsible for disseminating UX guidelines and best practices throughout the group. Collecting user requirements, participating in the design of business applications, organising information architecture, and working in collaboration with IT and other departments.
Working as a UX designer in section 574 (innovation) at the SNCF in Nantes. In charge of designing personas, user paths, and screen ergonomics for different applications.
An apprentice for 2 years and trained as a web designer with a specialization in UX design, working on several projects and building up solid experience in a field I'm passionate about.
Helping designers, no matter their seniority, to grow and giving them feedbacks about their projects or career perspectives.
Master 2, UX Design
Bachelor, Design (L3)
Web-Concepteur
I have written a few articles on various subjects, such as design, design systems, and user research.
Guillaume CAILLET on Medium →Design System · Design Ops · Automation
Interaction Design · Pattern Design · Industrial SaaS
Design Ops · Tooling · Figma Plugin
Design System · Audit · Design Ops
Product Design · Strategy · Sales Enablement
Design System · Research · Product Design
Product Design · Research · UI Design
Product Design · Research · UI Design
Product Design · Research · UI Design
Earlier projects: concept work, prototypes and student projects I still find relevant.
Structuring and development of the PrestaShop Design System. Provide product and core teams with access to a system that enables them to design coherent, fluid and easily structured experiences.
When I joined in June 2022, the PrestaShop "design system" was a set of advanced UI kits in Figma, not shared as a true library. Product designers worked with their own components, tech teams used a separate framework, and interface consistency was weak.
With multiple touchpoints (main product, help center, marketplace, academy), alignment was critical to scaling both product and brand.
Unifying three fragmented PrestaShop accounts (Back Office, Marketplace, Business Care) into one, so users finally stop calling support to update an email.
Cutting authentication errors in half by redesigning sign-in across the entire PrestaShop ecosystem (back office, marketplace, help center).
Redesign of the association flow between the user account and the shop, making it transparent and error-resistant.
The shop association process, particularly for open-source installations, was a major source of confusion. Merchants didn't understand why association was required and abandoned the process, especially when errors occurred.
The association exists because most users have Open Source shops installed locally on their hosting, not always identified as belonging to the owner account. Association creates this connection.
Executing the design system remediation plan: rebuilding 44 components, applying 2,634 token bindings, and establishing a dev-alignment workflow that accelerates feature delivery by 20–30%.
box-shadow: 0 2px 8px #3f64ff40;
background: #3f64ff;
border: 1px solid #1a1a2e;
box-shadow: {shadow.button.default};
background: {color.brand.primary.default};
border: 1px solid {color.neutral.900};
A JavaScript plugin built with the Figma Plugin API to automate local component audits, reducing DS audit time from days to hours.
A systematic Opal DS audit, graded findings against four industry frameworks, with a phased remediation plan I executed over the following months.
| Component | Token usage | Naming | Accessibility | Status |
|---|---|---|---|---|
| Button | ✗ | ⚠ | ✓ | NON-COMPLIANT |
| TextField | ⚠ | ✓ | ⚠ | NEEDS WORK |
| Chip | ✓ | ✓ | ✓ | COMPLIANT |
| Dialog | ✗ | ✗ | ⚠ | NON-COMPLIANT |
| Switch | ✓ | ✓ | ✓ | COMPLIANT |
From 8 manual steps in Excel to 1 action with real-time feedback, enabling a major automotive manufacturer to unlock multi-site deployment.
One coupled pattern: multi-select triggers a sticky action bar, so schedulers can update 50 work orders in one click instead of fifty. Same behavior across cards and Gantt views.