👨‍💻 After working two years as a Product Designer at Nielsen in Warsaw, and one year as Design Engineer / Front End Developer at wibas etarate in Hamburg, I decided to switch my career to become a UX engineer. Now, I have four years of experience in front end development. 💡 Currently, I am working as Senior Front End Developer @ GIE G5 Languedoc 💼 Through my studies, bootcamps in UX / UI Design, Web Development and AI Engineering, MSc in Creative Technology, and Masters in Marketing and Advertising, I have gained skills in user research, UI and UX design, development languages, AI and LLMs. My current position is Senior Front End Engineer @ GIE G5 Languedoc in Nîmes (FR), working on the website Parasanté online. 🗣 I am fluent in French and English. 🖥 I am technically proficient in: HTML | SCSS | JS | React | Liquid | Git | Github | Figma | Node.js | Express | MongoDB, and have knowledge in: Python | Flask | SQLite | Handlebars | Webflow | Adobe suite. ✉️ If my profile interests you, you can contact me here or by email at _Email not available. Sign in: https://www.twine.net/signup_ 📓 Check my portfolio here: _Website not available. Sign in: https://www.twine.net/signup_

Julien Sebag

👨‍💻 After working two years as a Product Designer at Nielsen in Warsaw, and one year as Design Engineer / Front End Developer at wibas etarate in Hamburg, I decided to switch my career to become a UX engineer. Now, I have four years of experience in front end development. 💡 Currently, I am working as Senior Front End Developer @ GIE G5 Languedoc 💼 Through my studies, bootcamps in UX / UI Design, Web Development and AI Engineering, MSc in Creative Technology, and Masters in Marketing and Advertising, I have gained skills in user research, UI and UX design, development languages, AI and LLMs. My current position is Senior Front End Engineer @ GIE G5 Languedoc in Nîmes (FR), working on the website Parasanté online. 🗣 I am fluent in French and English. 🖥 I am technically proficient in: HTML | SCSS | JS | React | Liquid | Git | Github | Figma | Node.js | Express | MongoDB, and have knowledge in: Python | Flask | SQLite | Handlebars | Webflow | Adobe suite. ✉️ If my profile interests you, you can contact me here or by email at _Email not available. Sign in: https://www.twine.net/signup_ 📓 Check my portfolio here: _Website not available. Sign in: https://www.twine.net/signup_

Available to hire

👨‍💻 After working two years as a Product Designer at Nielsen in Warsaw, and one year as Design Engineer / Front End Developer at wibas etarate in Hamburg, I decided to switch my career to become a UX engineer. Now, I have four years of experience in front end development.

💡 Currently, I am working as Senior Front End Developer @ GIE G5 Languedoc

💼 Through my studies, bootcamps in UX / UI Design, Web Development and AI Engineering, MSc in Creative Technology, and Masters in Marketing and Advertising, I have gained skills in user research, UI and UX design, development languages, AI and LLMs. My current position is Senior Front End Engineer @ GIE G5 Languedoc in Nîmes (FR), working on the website Parasanté online.

🗣 I am fluent in French and English.

🖥 I am technically proficient in: HTML | SCSS | JS | React | Liquid | Git | Github | Figma | Node.js | Express | MongoDB, and have knowledge in: Python | Flask | SQLite | Handlebars | Webflow | Adobe suite.

✉️ If my profile interests you, you can contact me here or by email at Email not available. Sign in: https://www.twine.net/signup

📓 Check my portfolio here: Website not available. Sign in: https://www.twine.net/signup

See more

Experience Level

Expert
Expert
Expert
Expert
Expert
Expert
Intermediate

Language

French
Fluent
English
Fluent
German
Beginner
Spanish; Castilian
Beginner

Work Experience

Senior Front-End Developer at Marmalade
July 1, 2024 - September 22, 2025
Built agency-owned products using React and Next.js. Contributed to client projects using Angular, delivering scalable front-end architectures, improving load performance by 25%.
Front-End Developer at Nielsen
January 31, 2024 - September 22, 2025
Developed internal tools in React, TypeScript, and GraphQL.
Product Designer
September 1, 2021 - September 22, 2025
Created a component library, which I coded in my Front End Developer position.
Front-End Developer at Venture Leap
July 1, 2022 - September 22, 2025
Front-end development for several clients of the agency, working mainly with Symfony.
Product Designer at Nielsen
January 1, 2020 - September 30, 2021
UX/UI Design for different products owned by the company. Building a global design system used on several products of the company. Mockups of a PWA helping panelists to manage their account, used in more than 30 countries, and translated in more than 35 languages, including RTL languages.
Design Engineer at wibas etarate
October 15, 2018 - December 31, 2019
UX/UI Design & Front End Development for several clients of the agency. Mockups of websites managed by the company. Graphic design of corporate resources. Scrum Master of the development team.

Education

AI Engineering Bootcamp at Ironhack, Remote
May 1, 2025 - July 4, 2025
Bootcamp focused on Artificial Intelligence, Machine Learning, and data analysis.
Web Development Bootcamp (MERN stack) at Ironhack, Berlin
January 1, 2021 - September 22, 2025
Bootcamp focused on MERN stack. Projects: JavaScript game, event app, artists booking app
UX / UI Bootcamp at Ironhack, Paris
January 1, 2018 - September 22, 2025
Projects: design for iOS apps, UX and UI: design thinking, user research, personas, wireframing, prototyping on Sketch and Flinto.
MSc Creative Technology at Middlesex University, London
January 1, 2016 - January 1, 2017
Final project: Mobile application and website for real estate, helping people to find easily a place to live.
Master's degree in Marketing and Advertising at IS COM, Lyon
September 17, 2012 - August 31, 2016
Dissertation title: The share of m-commerce in online purchases, or how mobile apps will take over websites.

Qualifications

Add your qualifications or awards here.

Industry Experience

Software & Internet, Professional Services, Media & Entertainment, Education
    paper React generator chatbot

    Challenge

    For this project, I had to create a chatbot. I built an AI-powered React component generation service that transforms text descriptions and UI mockup images into production-ready React code using OpenAI’s GPT-4 and Vision models.

    Key Features Implemented

    Smart Code Generation: Natural language to React/TypeScript components with Tailwind CSS styling by default.
    Image Analysis: Upload UI mockups and get corresponding React code using OpenAI Vision API.
    Contextual Learning: Vector similarity search via Pinecone database for relevant code examples.
    Interactive Chat Interface: Real-time conversation-based development workflow with session management.
    Automated Knowledge Base: Population from HuggingFace datasets and custom code snippets.

    Technical Architecture

    Backend: Flask API with OpenAI integration, MongoDB for storage, Pinecone for vector search, Cloudinary for image processing.
    Frontend: React/TypeScript with Vite, featuring drag-drop image upload, real-time messaging, and code syntax highlighting.
    AI Pipeline: LangChain orchestration with LangSmith monitoring, custom prompt engineering for React best practices.

    Special Features

    Automatic detection of boilerplate requests redirects users to my custom CLI tool (@julseb-lib/julseb-cli), showcasing a complete AI-powered development ecosystem.

    See the full project here: [https://www.twine.net/signin
    [See the project on Github](https://www.twine.net/signin

    paper @julseb-lib

    Tired of using Bootstrap and other heavy CSS frameworks, and reusing a lot of components at my job and in my personal projects, I decided to create my own React components library to save time on the development process. The idea of julseb-lib was to make a lightweight, complete, easy to use and to personalise components library. It is of course responsive. I decided to use TailwindCSS to ease the development process and personalisation.

    Library

    Design and development of the library in React and TailwindCSS.

    Utils

    Creation of an npm package with basic TypeScript functions.

    CLI

    Creation of a CLI to generate boilerplates using this library.

    See the project here; [https://www.twine.net/signin
    [See the project on Github](https://www.twine.net/signin