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Nicolas Fez
Verified Expert in Engineering
Full-stack Developer
Paris, France
Toptal member since September 1, 2026
Bio
Nicolas is a full-stack developer with 11 years of experience taking web and mobile applications from idea to production, across React, Next.js, React Native, Node.js, and Python. He now builds AI-driven products, including autonomous agents, MCP servers and clients, and LLM integrations. Nicolas created AssistXR for Valeo, unveiled at CES 2025, and created a marketplace serving over 3,000 users.
Portfolio
Valeo
React, Next.js, Node.js, Python, React Native, Expo, Google ADK...
FoodFlow
React, TypeScript, Odoo, Python, Next.js, GraphQL, Tailwind CSS, Front-end...
BBonds
MongoDB, Jest, Kubernetes, NATS, Docker, Skaffold, Node.js, Ethereum, Ethers.js...
Experience
- Node.js - 7 years
- JavaScript - 7 years
- Python - 7 years
- TypeScript - 5 years
- Next.js - 4 years
- Expo - 3 years
- React Native - 3 years
- Claude Agent SDK - 1 year
Work Experience
Full-stack and AI Engineer
2023 - PRESENT
Valeo
- Contributed to an agentic AI product spanning a Next.js web app and a React Native mobile client, built on a multi-agent architecture using Google ADK and the A2A protocol.
- Built an MCP server that bridges AI agents to the vehicle's CAN bus, enabling programmatic control of physical functions such as turn signals, windows, etc., from the agent system.
- Worked on AssistXR, an assistance service that connects a vehicle to operators so they can take charge of it during a breakdown (bCall) or emergency (eCall), on behalf of insurance companies. The service was demoed at CES 2025.
- Architected both AssistXR front ends end to end: a React web operator interface and an in-car application on Android Automotive OS, accessing vehicle telemetry and camera feeds via VHAL (Car Manager) and EVS.
Technologies: React, Next.js, Node.js, Python, React Native, Expo, Google ADK, Model Context Protocol (MCP), Vertex AI, Kotlin, Android Automotive, Amazon Web Services (AWS), Bash, Git, REST APIs, NoSQL, Jest, Three.js, Tailwind CSS, Claude Code, Android, Front-end, Back-end, Full-stack, Mobile, Google Cloud Platform (GCP)
Full-stack Developer
2023 - 2023
FoodFlow
- Built the B2B marketplace on top of the existing food delivery platform, including producer onboarding, profiles, and promotion, letting restaurants order directly from them. The platform now serves 3,000+ clients in production.
- Shipped the marketplace front end with Next.js and TypeScript.
- Extended the Python-based Odoo business layer, including B2B invoicing between producers and restaurants.
Technologies: React, TypeScript, Odoo, Python, Next.js, GraphQL, Tailwind CSS, Front-end, Back-end, Full-stack, Stripe, Vercel
Back-end Developer
2022 - 2023
BBonds
- Designed and built Node.js microservices for a fundraising platform on the Ethereum blockchain using Ethers.js.
- Built event-driven communication between services with NATS Streaming.
- Implemented meta-transaction signing via MetaMask and application-level ACLs.
- Operated in a full microservices stack spanning Docker, Kubernetes, Skaffold, Sentry, and GitLab CI.
Technologies: MongoDB, Jest, Kubernetes, NATS, Docker, Skaffold, Node.js, Ethereum, Ethers.js, MetaMask, GitLab CI/CD, Sentry, TypeScript, Express.js, NoSQL, Tailwind CSS, Back-end, Microservices, Fintech
Full-stack Developer
2021 - 2022
Thales
- Delivered features for an internal ERP focused on project cost and value optimization at Thales.
- Integrated a staffing tool for assembling project squads and assigning resources to teams.
- Built with React and Node.js (Express) in a Docker, Kubernetes, and GitLab CI containerized environment.
Technologies: Redux, MySQL, Jest, React, Node.js, Docker, Kubernetes, GitLab CI/CD, Tailwind CSS, Express.js, SQL, Front-end, Back-end, Full-stack
Software Engineer
2019 - 2021
Dassault Aviation – Capgemini
- Worked on embedded C and Assembly software for avionics systems on the Dassault Rafale at Dassault Aviation.
- Contributed to the integration of target localization and weapon-system algorithms.
- Wrote unit tests with CUnit and automated build and test routines in Bash and Python.
Technologies: Assembly, Bash, C, Python, Back-end
Software Engineer
2019 - 2019
Sopra Steria
- Architected ETL pipelines and data transformation workflows processing large volumes from the SNIIRAM national healthcare database.
- Diagnosed and fixed the C++ CAMEL data processing application: resolved long-standing crashes caused by stack overflows and missing array terminators, and lifted its 2 GB file-size limit by migrating from 32-bit to 64-bit integer types.
- Built an internal application cataloging the SNIIRAM applications, with a Neo4j-powered graph visualization of the relationships between them.
- Developed a chatbot for searching the group's internal documentation with a team of fellow interns, delivered as a cross-platform mobile app with Ionic, Cordova, and Angular.
Technologies: C++, Neo4j, PL/SQL, Oracle, Angular, Ionic, Cordova, Business Intelligence (BI), Front-end, Back-end, Full-stack
Teaching Assistant
2018 - 2019
Web@cadémie
- Mentored students in professional retraining across the full web stack.
- Spearheaded project evaluations, reviewing student code and assessing deliverables.
- Prepared the training materials used throughout the program.
Technologies: CSS, HTML, JavaScript, MySQL, PHP, Symfony, React, SQL, Sass, Front-end, Back-end, Full-stack
Software Developer
2017 - 2017
Cadageo
- Built Splicy from scratch, including a QGIS plugin written in Python for visualizing fiber optic splices and cassettes in FTTH network deployments.
- Connected the plugin in real time to an Angular web interface over WebSockets, keeping both views in sync.
- Optimized the PostgreSQL queries serving the network data, improving response times on large datasets.
Technologies: CSS, HTML, PostgreSQL, Python, Socket.IO, Angular, PostgreSQL 9, SQL, Front-end, Back-end, Full-stack
Software Engineer
2015 - 2015
Orchestra Travelsoft
- Contributed to the development of websites for tour operators within a Java/JEE engineering team.
- Built server-side features with Enterprise JavaBeans (EJB) and Apache Struts on an Oracle database.
- Developed load-testing scenarios with Locust to evaluate platform performance.
Technologies: CSS, HTML, Java, JavaScript, JEE, Oracle, Python, Locust, SQL, Front-end, Back-end, Full-stack
Project History
Valeo AssistXR
Valeo AssistXR is a connected assistance solution that combines real-time vehicle sensor data with cloud and AI capabilities. Using onboard equipment, it delivers faster, more accurate support without additional hardware. Unveiled at CES 2025, it enables call centers to access real-time data and video for eCall (emergency), bCall (breakdown), and sCall (maintenance). With digital twin visualization and 360-degree PanoramaXR view, Valeo AssistXR enhances safety, efficiency, and user experience.
Nextrip — AI Travel Companion
http://nextrip.nicolasfez.com/Nextrip is an AI-powered travel companion that helps users discover destinations tailored to their taste, budget, season, climate preferences, and travel pace. Instead of generic top-10 lists or viral travel trends, Nextrip recommends places that genuinely match each user’s profile. The app lets travelers explore 195+ countries, browse by continent, read rich destination guides, save favorites, and get smarter suggestions over time. Free, multilingual, and privacy-focused.
Education
2014 - 2019
Master's Degree in Computer Science
Paris Graduate School of Digital Innovation (EPITECH) - Paris, France
2018 - 2018
Course in Computer Science
California State University of San Marcos - San Marcos, CA, USA
Skills
Libraries/APIs
Node.js, REST APIs, React, Three.js, Stripe, Socket.IO
Tools
Git, WebStorm, PyCharm, Claude Code, Expo, Claude Agent SDK, Wireshark, GitLab CI/CD, MetaMask, Sentry, Odoo
Languages
Bash, C, Python, CSS, HTML, JavaScript, TypeScript, SQL, C++, Sass, Embedded C, Kotlin, Assembly, PHP, Java, GraphQL, Assembler x86
Frameworks
Next.js, React Native, Jest, Redux, Express.js, Tailwind CSS, Unity, Symfony, Angular, Locust, Ionic, Genkit
Paradigms
Microservices, Model Context Protocol (MCP), Business Intelligence (BI)
Platforms
Android, Mobile, Docker, Vertex AI, Android Automotive, Amazon Web Services (AWS), Vercel, Google Cloud Platform (GCP), iOS, RevenueCat, Kubernetes, JEE, Oracle, Ethereum, Firebase
Storage
MySQL, PostgreSQL, MongoDB, NoSQL, Neo4j, PL/SQL
Other
Front-end, Back-end, Full-stack, Computer Science, Computer Networking, Internet Protocols, ARM Embedded, Entrepreneurship, PostgreSQL 9, Fintech, NATS, Skaffold, Game Development, Cordova, Ethers.js, Google ADK
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