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Senior Software Engineer · Hong Kong

Sébastien Friedberg

Engineer + Full-Stack, React, Next.js, React-Native, Java / Spring, AI / LLM, Cloud, and Founder

00About

Engineer, end to end.

Hi, I'm Sébastien — a Senior Software Engineer based in Hong Kong, shipping React and Next.js products end-to-end. Currently at Société Générale on FX trading systems, and co-founder & CTO of Symphone, a music-tech startup.

Contact me on LinkedIn
01Skills

What I work with

  • JavaScript
  • TypeScript
  • Java
  • Swift
  • Kotlin
  • C#
  • Python
  • Ruby
  • SQL
  • React
  • React Native
  • Expo
  • Next.js
  • Tailwind
  • Apollo / GraphQL
  • Three.js
  • Spring Boot
  • Ruby on Rails
  • Nest.js
  • Node.js
  • REST
  • Firebase
  • MySQL
  • AWS
  • GCP
  • Shopify
  • Jenkins
  • Git
  • Linux / Shell
  • BLE / Arduino
  • Mistral AI
  • French (native)
  • English (TOEIC 950)
  • Spanish
  • Mandarin (basics)
02Experience

Where I've worked

  1. Nov 2024 — Present · Hong Kong

    Société Générale

    Software Engineer — FX & Pre-Trade

    Internal full-stack tooling for global FX and post-trade trading systems. Backend in Java/Spring Boot, UI in React/Tailwind. Cross-timezone collaboration across HK ↔ Paris ↔ APAC.

    • Java
    • Spring Boot
    • React
    • Tailwind
    • C#
  2. Paris

    Symphone

    Co-Founder & CTO

    Co-founded a music-tech startup. Sole engineer end-to-end: custom-PCB hardware, firmware, iOS/Android apps, Firebase backend, and Shopify e-commerce. Successful Kickstarter and product launch.

    • React-Native
    • Expo
    • Firebase
    • GCP
    • Swift
    • Kotlin
    • Arduino
    • BLE
    • Shopify
  3. World

    Freelance

    Full-Stack Engineer

    End-to-end frontend ownership across multiple side engagements. Flagship: PassCE — web app + Expo mobile app for a corporate benefits platform reaching 10,000+ daily users.

    • React
    • React-Native
    • Expo
    • Firebase
    • Tailwind
    • TypeScript
  4. Mar 2020 — Sep 2020 · Paris

    Crédit Agricole Technologies & Services

    Software Engineer

    Software engineering inside the bank's internal technology division. Backend and frontend work on banking applications.

    • Java
    • MySQL
    • JavaScript
    • HTML
    • CSS
03Education

Education

  1. Software engineering school

    EFREI Paris

    Software Engineering — MSc

    Paris, France
  2. Image processing & Artificial intelligence

    Universitat Politècnica de Catalunya

    Image Processing & Artificial Intelligence — Exchange

    Barcelona, Spain
  3. Software & data engineering

    Concordia University

    Software & Data Engineering — Exchange

    Montreal, Canada
04Intelligence

Building with AI

I build AI-powered products end-to-end — integrating LLMs and retrieval-augmented generation into real apps, plus hands-on work in reinforcement learning and image processing.

  1. LLMs & RAG

    Building retrieval-augmented generation into full-stack products — grounding language models in real data.

  2. Reinforcement Learning

    Agents that learn from interaction, improving their policy through reward and feedback over time.

  3. Computer Vision & AI

    Image processing and applied AI — from classical pipelines to learned models.

A scripted, front-end demo assistant — no live model, just a quick way to explore my work.

05Cities

Where I've been

WorkStudies
  • Montreal

    Canada

    2019 – 2020

    Exchange · Concordia University

  • Paris

    France

    2020 – Present

    Co-founder & CTO · Symphone

  • Barcelona

    Spain

    2021 – 2022

    Exchange · Universitat Politècnica de Catalunya

  • Shenzhen

    China

    2023 – Present

    Hardware manufacturing · Symphone

  • Hong Kong

    2024 – Present

    Senior Software Engineer · Société Générale

06Projects

Selected work

  1. Pick — Choose your best photo

    Solo product · iOS & Android · Expo

    A consumer mobile app that helps people pick the most impactful photo of themselves — for LinkedIn, dating profiles, anywhere. Solo product: concept, UX, mobile (Expo), and companion site. Available on App Store and Google Play.

    Pick — Choose your best photo — project preview
  2. MyPhotograph — Photographer marketplace

    Solo product · iOS · Expo + Next.js

    A two-sided mobile marketplace connecting users with photographers — like "Uber for photo sessions." Solo product: concept, UX, Expo mobile app, and Next.js companion site. Shipped on the App Store.

    MyPhotograph — Photographer marketplace — project preview
  3. PassCE — Corporate benefits platform

    Freelance · Web + Mobile · PHP backend

    Web app + Expo mobile app for a French corporate benefits platform. Built the entire frontend as a freelance engagement, reaching 10,000+ daily active users. Backend (PHP) maintained by the client team.

  4. Spotify Profiler

    Class project · React + Node.js · Efrei Paris

    Find lyrics for your favorite tracks and explore listening statistics. Built in React and Node.js as a class project at Efrei Paris (before Spotify added lyrics natively).

    Spotify Profiler — project preview
07Contact

Get in touch

I'm always open to interesting projects and conversations. Reach out and let's build something.