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.
Availability: Currently at Keolis Group
Frontend Software Engineer · Web Accessibility & Performance
Working remotely at Keolis, previously Decathlon e-commerce across 15+ markets. I build accessible, high-performance storefronts and design systems with React, Next.js and Svelte.
About me
Hi, I'm Kévin Sauvage
Current role: Currently at Keolis Group (remote) — accessibility, axe in CI
Frontend engineer with 5+ years building web products used by millions of people across 15+ countries. Most of my work is on accessibility, performance and shared component libraries.
At Keolis I took ilévia, a French public transit platform, from 30% to 84% RGAA compliance and added accessibility checks (Jest-axe, Cypress-axe, ESLint jsx-a11y) to CI so regressions don't reach production.
At Decathlon I built the Svelte component library behind the storefronts in 15+ countries and cut load time on the Spanish site by 1.5s through Core Web Vitals work.
Stack: React, Next.js, TypeScript, Svelte, Jest, Cypress, Storybook.
Based in Barcelona, fluent in English, French and Spanish.
Languages
- FrenchNative
- EnglishC1 Certified
- SpanishFluent
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.
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 – PresentTook RGAA compliance on ilévia, a French public transit platform, from 30% to 84%. Audited the UI and reworked core components: semantic HTML, ARIA, keyboard navigation and screen reader support.
Added Jest-axe and Cypress-axe to the CI/CD pipeline so accessibility regressions get caught before production.
Set up ESLint (jsx-a11y plus custom rules) as a required check on every pull request.
Worked with product and design so accessibility is part of the job from wireframe to release.
Next.jsReactTypeScriptTailwindJest-axeCypress-axeESLintjsx-a11yARIASemantic HTMLAccessibility
Decathlon Core
Frontend Software Engineer
Oct 2023 – Dec 2025Built a Svelte component library that now runs e-commerce storefronts in 15+ countries.
Moved the checkout out of a monorepo into a versioned npm package (Lerna), with Strapi feature flags and per-country configuration.
Ran A/B tests on conversion and adoption across international markets.
Worked with designers in Figma and Storybook to ship accessible, well-tested components.
Owned the test suite (Jest, Cypress): more coverage, fewer production incidents.
SvelteJavaScriptStorybookJestCypressFigmaTailwindAccessibility
Decathlon Spain
Frontend Software Engineer
May 2022 – Oct 2023Improved Core Web Vitals on the Spanish storefront: average load time down 1.5s, higher Lighthouse scores.
Built a modular Svelte component system that cut duplication and sped up new product features.
Rolled out WCAG 2.1 across the storefront.
Wrote the team's documentation standards for components and technical decisions.
SvelteJavaScriptCore Web VitalsTailwindPerformanceAccessibility
Subforce
Frontend Software Engineer
Jun 2021 – May 2022Built full-stack features in React, Next.js, Node.js and Express.js, including third-party API integrations.
Designed state management with Redux and Context API for complex UIs.
Moved a legacy JavaScript codebase to ES6+, which cut bugs and made it easier to maintain.
ReactNext.jsReduxNode.jsExpress.jsMongoDBJavaScriptSass
Testimonials
What Colleagues Say
A few words from colleagues and managers I have had the chance to work with.
01 / 03
"From day one, he showed a rare ability to take on the most complex technical challenges and find pragmatic solutions. His ability to adapt quickly, understand the bigger picture, and deliver impact made him an invaluable asset in both contexts. I would gladly work with Kevin again — any organization would be lucky to have him."
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.
Design & development (solo) · 2026
ORUVA — Jewelry E-Commerce
ORUVA is a live European jewelry label selling everyday rings, necklaces, earrings and bracelets to shoppers in Spain and France. I designed and built the whole storefront on Next.js 16 and Shopify: a three-language catalog, persistent cart, customer accounts, wishlist and predictive search, with content managed in Shopify rather than in code.
Live demo in English, Spanish and French
Brand copy, menus, policies and page content editable in Shopify, no redeploy needed
Storefront + Admin APIs typed end-to-end with GraphQL Code Generator
Automated accessibility (axe, WCAG 2.1 AA) and add-to-cart smoke tests in Playwright
Next.js 16React 19TypeScriptShopify Storefront APIShopify Customer Account APIShopify Admin APIGraphQLGraphQL Code Generatornext-intlTailwind CSS 4Radix UIshadcn/uiServer ActionsZodUpstash RedisPlaywrightVercel
Design & development · 2026
ComplyLoop — Accessibility Compliance
ComplyLoop checks React and Next.js codebases for accessibility against RGAA 4 and WCAG 2.2. It scans the source, optionally audits the running site, opens fixes as draft pull requests, and keeps an evidence log of every step. It is aimed at French agencies that deliver RGAA-regulated sites for several clients.
Source scan (AST checks and jsx-a11y) plus runtime audits with Playwright and axe
A finding only closes once a re-run confirms the fix; AI never sets a status
Append-only evidence log, exportable as JSON, Markdown or HTML
Public repository, with CI, unit tests and Playwright end-to-end specs
Next.js 16React 19TypeScriptPostgresDrizzle ORMAuth.jsGitHub App (Octokit)GitHub ActionsPlaywrightaxe-coreVercel AI SDKZodTailwind CSS 4VitestSentry
Credentials
Continuous Learning
Production work is my main credential — these formalize the rest. Right now that means accessibility depth, JavaScript fundamentals, and working across three languages.
Deepening Web Accessibility
Self-directed · In Progress
•Going deeper on WCAG 2.2, ARIA authoring practices, and screen-reader testing — applied directly to Keolis delivery and axe-gated CI pipelines.
WCAG 2.2ARIAScreen Readers
C1 English Certificate
EF SET
•Official C1 Advanced English certification for professional communication in international environments.
C1 Advanced EnglishInternational Collaboration
View CredentialReact: Using TypeScript
LinkedIn Learning
•Course on building type-safe React applications with TypeScript — props, hooks, and patterns for complex front-ends.
ReactTypeScriptType Safety
View CredentialJavaScript: The Advanced Concepts
Udemy
•Advanced JavaScript course covering closures, prototypes, async programming, and modern ES6+ features for complex applications.
Closures & PrototypesAsync PatternsES6+
View CredentialFull-Stack Web Developer Bootcamp
Le Wagon
•Where I started: 9-week intensive bootcamp covering Ruby on Rails and JavaScript. Since then, 5+ years of production React, Svelte, and Next.js work.
Full-Stack FoundationsRuby on RailsJavaScript
View CredentialFAQ
Questions, Answered
The things people usually ask before getting in touch — answered upfront so you don’t have to.
I'm currently a Frontend Software Engineer at Keolis Group, working remotely from Barcelona — and I'm always open to connections and interesting conversations. The fastest way to reach me is the contact form or email below; I reply within 24 hours on weekdays.
My day-to-day focus is my full-time role at Keolis, so I only consider small, well-scoped collaborations — audits, code reviews, or mentoring. Tell me what you have in mind and I'll give you a straight answer.
React, Next.js, Svelte, and TypeScript, with Tailwind CSS, Storybook, and testing built on Jest, Cypress, and axe. My specialties are web accessibility, design systems, and Core Web Vitals performance.
Yes. Decathlon and Keolis work is proprietary, but I can walk through NDA-friendly summaries: architecture decisions, metrics like the −1.5s LCP improvement, and lessons learned. Just ask.
Barcelona, Spain (CET, UTC+1), working remotely. I work in French (native), English (C1, EF SET), and Spanish (fluent) — comfortable in multicultural, distributed teams.
Contact
Let's connect
Based in Barcelona, working remotely at Keolis Group. Always open to interesting conversations and opportunities — feel free to reach out.
Barcelona, Spain — CET (UTC+1) · English, French, Spanish