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Sylvain LaconiSL

Sylvain Laconi

Expert React/Node · Business Tools & SaaS

€490/day
3 projects
Paris, FR
3-7 years

Average response time: 1 hour

Freelancer profile translated to English.
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About Sylvain

I design web applications for teams that waste time switching between too many tools: re-keying data, back-and-forth communication, repetitive tasks, and information scattered everywhere.

After 13 years managing logistics sites (Decathlon — teams, processes, budget), I've spent over 5 years developing digital products for startups, SMEs, and scale-ups, and providing technical support for agencies.

What I handle:
  • Business tools and back-offices that centralize and standardize operations (React, TypeScript, Node.js, PostgreSQL / Supabase)
  • MVP and SaaS evolution (auth, multi-roles, permissions, performance)
  • Refactoring and structuring of existing React applications
  • Workflow automation between tools (APIs, exports, business rules) when multiple systems need to cooperate
  • Standalone marketing websites and landing pages (Webflow, or React with Next.js when SEO / SSR / velocity justify it)

What you gain concretely:
  • Less daily friction: less double entry, fewer errors, less "doing the same thing manually over and over"
  • Tools that communicate with each other — or a single point of access — to speed up processes and make decisions based on consistent data
  • A reliable partner who understands your operational needs (adoption, deadlines, reliability)

Technologies:
  • Core stack: React, TypeScript, Node.js, PostgreSQL (Neon, Supabase), Prisma
  • Next.js when it's the right product choice (MVP, full-stack, SEO, rapid deployment)
  • As needed: Retool (rapid back-office), Webflow (marketing)

Recent clients: circular economy (Weturn), custom digital products (X-Studio, Brulance, Lonestone)

→ Let's talk about what's wasting your time today — and the tool or release that can eliminate it.
  • French

    Native or bilingual

  • English

    Fluent

Remote only
Primarily works remotely

Experience

  • Funérarium Fontaine
    Full-stack Developer · Operational Management SaaS (Funeral Home)
    SOFTWARE PUBLISHING
    October 2025 - Today (10 months)
    Charleroi, Belgium
    Context
    Fontaine Funeral Home (Belgium): replacing fragmented processes (multiple tools, manual entries) with a single platform to manage funeral files, teams, and business obligations.

    My Role
    Full-stack development on a product monorepo (React business web app, tRPC API, Next.js public site): new features, bug fixes, quality assurance, and platform evolution in production.

    Business Impact
    • A single tool for admin and field teams (procedures, contacts, documents, workflows)
    • Reduction in errors and time lost between systems
    • A scalable foundation (multi-organization, sensitive data, traceability)

    Delivery / Development Cost Impact
    • Streamlined product pipeline: Linear → assisted development (Cursor) → GitHub → preview builds per PR (Neon, Cloudflare) → deployment via Fly.io
    • Faster and less risky iterations (preview environments, CI, code reviews)
    React.js TanStack Router tRPC TypeScript DrizzleORM
  • X-Studio
    Full-stack Developer · SaaS & Business Tools
    DIGITAL AND IT
    January 2025 - Today (1 year and 7 months)
    Colombes, France
    Context
    X-Studio is a digital product agency. I provide full-stack support for SaaS, business tools, and websites for startup and brand clients.

    My Role
    Independent throughout the entire cycle: technical scoping, development, optimization, and redesign. Emphasis on code quality, user experience, and performance — for tools that are actually used daily, not just delivered.

    Key Projects

    *Wastetide— Circular economy project management platform. Multi-organization, roles, KPIs, and dashboards to track activity without scattered spreadsheets.

    *Swipelink & Curiousquad— Business web applications (React, Node API): user journeys, authentication, fine-grained permissions, and dynamic interfaces based on profiles.

    *X-Tract— Web application for managing emergency response at sporting events: multi-project access, roles, performance calculations, and conditional views to help teams make faster decisions.

    *École de Natation Française— Showcase website with a custom CMS (Directus): content editable without developer intervention for each update.

    *Artysquad, Maesina & X-Studio— Webflow marketing websites: polished design, animations, and content management autonomy for teams.
    TypeScript Next.js TailwindCSS Supabase Webflow
  • Weturn
    Full-stack Developer · Internal ERP & Field Data Collection
    LOGISTICS AND SUPPLY CHAIN
    July 2024 - December 2024 (5 months)
    Paris, France
    Context
    Textile circular economy startup — needed tools for operations and field teams.

    Monitor (Retool)
    Internal ERP centralizing projects, partners, and supply chains — business interfaces, automations, reporting. No more scattered files and tools.

    Valo (Next.js/Nest.js)
    Field web app for textile collection — multi-role authentication, filters, exports, mobile interface for operators.

    Result
    Two tools adopted daily, developed independently with strong business buy-in.
    TypeScript Next.js NestJs Auth0 Retool

Reviews

5.0

Out of 3 ratings

T

Titouan

X-Fabric SAS

Reviewed on 9/1/2025

As usual, Sylvain did an excellent job, it's always a pleasure to collaborate!
T

Titouan

X-Fabric SAS

Reviewed on 9/1/2025

Working with Sylvain is always a real pleasure. He is clear, efficient, and delivers quality results. Our discussions are always well-structured and concise, allowing for easy progress tracking and collaboration without wasted time. Fair, reliable, and professional, he brings peace of mind to projects.

Recommendations

Godefroy De CompreignacGD
Titouan ParandTP
CA
Godefroy De Compreignac and 2 other people have recommended Sylvain

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Education

  • Web / Mobile Web Developer Training
    Wild Code School
    2021
  • Engineering Degree in Industrial Systems
    University of Technology of Troyes
    2009

Certifications

  • First Certificate of English grade B2
    Cambridge Assessment English
    2007
    English

Skill set

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