Driving Impact
I build things that work. My goal is to create solutions that solve real problems and provide a smooth experience for users. I focus on delivering value that makes a difference.
Building Fast, Accessible Web Apps
I build fast, accessible web products used by millions across 15+ countries, including Decathlon's e-commerce platforms. My stack is React, Next.js, Svelte and TypeScript, with a strong focus on accessibility, testing and scalable component architecture.
About me
Hi, I'm Kévin Sauvage
I've spent 5+ years building web products used by millions across 15+ countries, including Decathlon's e-commerce platforms in Europe. I mostly work with React, Next.js, Svelte and TypeScript, and I care a lot about accessibility, testing and keeping codebases maintainable. I'm comfortable owning features from start to finish in fast-moving teams. Based in Barcelona, I work fluently in English, French and Spanish.
My Philosophy
Code Quality
I write clean, maintainable code and keep learning new tools and techniques to build better solutions. Good code saves time and makes everyone's job easier.
Collaborative Growth
I work best with others. I enjoy teams where we share knowledge, communicate openly, and help each other grow through feedback and collaboration.
Portfolio
Featured Projects
Here are some projects I've worked on. Each one is focused on speed, accessibility and real usability, and reflects how I think through problems and build things that hold up in production.
01
Modern E-Commerce Platform
A modern e-commerce demo built with Next.js 15 and TypeScript. Features product filtering, cart management, and checkout powered by Shopify's Storefront API. Achieves high Lighthouse scores for performance, accessibility, and SEO.
Next.jsReactTypeScriptShadCnTailwind CSSGraphQLShopify Storefront APIZod
Career
Professional Journey
Each role I've had has pushed me in a different direction. From building component libraries to tuning performance and accessibility, every step has made me a more well-rounded engineer.
Keolis Group
Frontend Software Engineer
Feb 2026 – PresentIntegrated Jest-axe and Cypress-axe into the CI/CD pipeline, preventing accessibility regressions from reaching production.
Enforced WCAG compliance at the source by configuring ESLint (jsx-a11y + custom rules) as a required gate on every pull request.
Refactored core UI components to enforce semantic HTML, ARIA, keyboard navigation, and screen reader standards.
Collaborated with product and design to make accessibility a first-class requirement from wireframe to release.
Next.jsReactTypeScriptTailwindJest-axeCypress-axeESLintjsx-a11yARIASemantic HTMLAccessibility
Decathlon Core
Frontend Software Engineer
Oct 2023 – Feb 2026Architected a Svelte component library now powering e-commerce storefronts across 15+ countries, standardising UI at scale.
Drove A/B testing initiatives that produced measurable lifts in conversion and user adoption across international markets.
Worked closely with designers in Figma and Storybook to ship pixel-perfect, accessible components with high test coverage.
Owned the full test suite (Jest, Cypress), raising coverage and reducing the rate of production incidents significantly.
SvelteJavaScriptStorybookJestCypressFigmaTailwindAccessibility
Decathlon Spain
Frontend Software Engineer
May 2022 – Oct 2023Improved Core Web Vitals on the Decathlon Spain storefront, cutting average load time by 1.5s and lifting Lighthouse scores.
Built a modular Svelte component system that cut duplication and accelerated delivery of new product features.
Rolled out WCAG 2.1 accessibility standards across the platform, meaningfully improving the experience for all users.
Established internal documentation standards for components and technical decisions, improving team knowledge sharing.
SvelteJavaScriptCore Web VitalsTailwindPerformanceAccessibility
Subforce
Frontend Software Engineer
Jun 2021 – May 2022Delivered full-stack features using React.js, Next.js, Node.js, and Express.js, including secure third-party API integrations.
Designed scalable state management patterns with Redux and Context API, improving data flow across complex UIs.
Modernised a legacy JavaScript codebase to ES6+ standards, cutting bug count and improving long-term maintainability.
ReactNext.jsReduxNode.jsExpress.jsMongoDBJavaScriptSass
Continuous Learning
Certifications & Achievements
I like keeping up with new tools and practices. These are a few certifications I have picked up along the way.
Full-Stack Web Developer Bootcamp
Le Wagon
•9-week intensive bootcamp covering full-stack development with Ruby on Rails, JavaScript, and modern web technologies. Built and deployed two production applications including an Airbnb clone.
Ruby on RailsJavaScript ES6HTMLCSSBootstrapSQLGitGitHubHerokuFull-Stack Development
View Credential for Full-Stack Web Developer BootcampJavaScript: The Advanced Concepts
Udemy
•Advanced JavaScript course covering closures, prototypes, async programming, and modern ES6+ features for complex applications.
JavaScriptProgrammingWeb DevelopmentFrontend Development
View Credential for JavaScript: The Advanced ConceptsC1 English Certificate
EF SET
•Official C1 Advanced English certification for professional communication in international environments.
EnglishCommunicationInternational Collaboration
View Credential for C1 English CertificateTestimonials
What Colleagues Say
A few words from colleagues and managers I have had the chance to work with.
01 / 03
"I had the pleasure of working with Kevin, an outstanding engineer and teammate. From day one, he showed a rare ability to take on the most complex technical challenges and find pragmatic solutions. Even while working in a legacy environment, Kevin brought fresh ideas and meaningful improvements to our front-end, raising the bar for quality and performance. Later, when he transitioned to a new team, Kevin's expertise drove some key changes that truly propelled us forward. His ability to adapt quickly, understand the bigger picture, and deliver impact made him an invaluable asset in both contexts. Beyond his technical excellence, Kevin is a fantastic collaborator, generous with his knowledge, supportive of others, and someone who elevates the team around him. I would gladly work with Kevin again in the future, and any organization would be lucky to have him."See more testimonials