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Jean-Charles BarqJB

Jean-Charles Barq

Full Stack Developer — B2B & SaaS

€500/day
Marseille, FR
3-7 years

Average response time: 1 hour

Freelancer profile translated to English.
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About Jean-Charles

The right product is one the team can maintain without you.


I helpB2B and SaaSteams transform **complex business needs into deliverable products**: from clarifying the need to production code.

Specifically, I don't just deliver React screens.
I work across the entire chain from "we have a vague business problem" to "we have a product the team can evolve":
  • requirements gathering,
  • Figma prototyping,
  • frontend architecture, React / TypeScript execution,
  • and lightweight backend when the project requires it (API, NestJS, auth, third-party integrations).
It's this dual role — product judgment + solid technical execution — that makes the difference when the need isn't perfectly defined yet, or when bridging the gap between product expectations, technical constraints, and user experience.

I am particularly relevant for:
  • B2B / SaaS products, dashboards, internal tools, or complex business interfaces;
  • contexts where deciding what to build is as important as how to build it;
  • refactoring or stabilizing difficult-to-maintain existing code.
My interventions notably cover: React / TypeScript interface development, dashboard design and redesign, functional prototyping and mockups, frontend structuring and feature-based architecture, maintainability improvement, API integration and lightweight backend, testing and securing critical workflows.

Main Stack: React, TypeScript, Next.js, TanStack Query, React Router, Tailwind CSS, Shadcn, Vitest, React Testing Library, Node.js / NestJS / REST API as needed.
  • French

    Native or bilingual

  • English

    Fluent

  • Spanish

    Conversational

Can work on-site
Marseille (up to 50km), Paris (up to 50km)

Experience

  • Scaleway
    Frontend Developer | UI/UX Support
    TECH
    August 2025 - Today (10 months)
    Paris, France
    Cloud Provider | Data Center | Feature-based architecture

    • Summary

    Technicalownerof an internal tool aimed at centralizing, within a single interface (“single source of truth”), several critical hardware team resources: component catalog management, assembly manual creation, commercial offer management, and physical asset tracking.

    Intervention with a **product-oriented approach**: gathering and clarifying needs from user teams, **prototyping features and full implementation**.


    • Contributions

    📌 Ownership of the development of a unified interface including:

    hardware catalog
    assembly manuals
    commercial offers

    🧭 Gathering and clarifying needs from hardware teams (direct discussions, use case formalization, understanding existing workflows).

    🎯 Structuring a feature-oriented architecture to isolate different business domains while maintaining overall product consistency.

    🎨 Lightweight prototyping of features (Figma) to validate functional paths and hypotheses before implementation.

    🔍 Auditing existing codebase and refactoring critical parts to reduce complexity and improve maintainability.

    ♻️ Factoring out components and implementing common patterns to accelerate the development of new features.

    ✅ Writing unit and integration tests (Vitest, RTL, MSW).

    📝 Implementing best practices and active participation in code reviews.

    • Main Stack

    React, React Router v7 (Data Mode), Material UI, Vite, Vitest, RTL, MSW, React Hook Form, Zod, TanStack Query, TypeScript, Feature-based architecture, Figma.
    React.js Front-End Development Figma UI/UX Design TypeScript
  • Stockoss
    Fullstack Developer React.js / Next.js / React Native / Nest.js
    LOGISTICS AND SUPPLY CHAIN
    December 2023 - February 2025 (1 year and 2 months)
    Paris, France
    Logistics SaaS | Web & Mobile | API | Growth Automation

    Summary:

    Participation in the development of the Stockoss SaaS platform's web and mobile solutions, in an agile context.

    Contributions:

    📌 Development of features on the SOO Client web platform (Next.js / React.js).
    ⚙️ Participation in the development of several APIs with NestJS in collaboration with the backend team.
    📱 Participation in the development of the WMS V1 and WMS V2 mobile apps (React Native).
    ✅ Contribution to the implementation of automated tests (Jest, React Testing Library).
    🚀 Development of a scraping tool with Puppeteer for growth hacking needs.
    📝 Participation in code reviews, delivery of maintainable and tested code.

    Main Stack: TypeScript, Next.js, React.js, React Native, NestJS, RTL, Jest, Puppeteer, AWS, Docker.
    React.js Next.js NestJs React Native
  • Direction Generale de l'Aviation Civile
    Javascript and Golang Developer | React.js | Node.js
    AVIATION AND AEROSPACE
    December 2022 - December 2023 (1 year)
    Toulouse, France
    R&D Context | Air Traffic Management Web Tools

    Summary:

    Work on DGAC R&D projects related to air traffic management.

    Contributions:

    🚀 e-FTM: design, architecture, and from-scratch development of the POC for the air traffic controller workload management tool.
    ⚙️ Participation in frontend and UX optimization efforts.
    🛠️ IODA-WEB and SINAPS: evolutionary and corrective maintenance of existing applications.

    Main Stack: React.js, WebComponents, TypeScript, Golang, Redux Toolkit, Material UI
    React.js JavaScript TypeScript Node.js Golang

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