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Nathan MercierNM

Nathan Mercier

Fullstack Developer (Java, Vue.js)

€550/day
Belley, FR
3-7 years

Average response time: 1 hour

About Nathan

👋 About me

Hi! I'm a backend-focused fullstack engineer with a Master's degree in Computer Science and 5+ years of professional experience. I specialize in Java / Spring Boot, with solid exposure to frontend (Vue.js) and mobile (iOS). I care deeply about code quality and clean architecture — a great developer writes code for others to read, not just for the machine to execute.

💼 Experience

  • Darwin → Crédit Agricole (2023 - now) - FREELANCE
Agile – SCRUM | Java 25, Spring Boot 3, Docker, Kubernetes, IntelliJ
Developing a banking application for one of France's largest banks, with a strong focus on robustness, scalability and modern Java best practices.
  • Kaibee → Tennaxia (2022 - 2023) - CDI
Agile – SCRUM | Java, Vue.js, Git, Maven, Hibernate, Docker
Delivered new features on HSE/CSR software platforms. First significant fullstack exposure, working across both Java backend and Vue.js frontend.
  • Sopra Steria → CNAF (2021 - 2022) - CDI
Agile – SCRUM | Java, Git, Maven, Hibernate
Built new features on an early childhood grant management platform. High-stakes environment with strong regulatory and business requirements.
  • Frenchsky (2021) - CDD
Waterfall | Java, Git, Maven, MySQL
Developed Minecraft plugins — a formative first professional experience that solidified my Java fundamentals.

📱 Personal projects

Alongside my backend missions, with the help of Claude Code, I develop an iOS application in Swift — giving me a broader product mindset and the ability to collaborate effectively with mobile teams.
I also manage my own home server and made my own personal assistant.

📚 Continuous Learning

CRAFT
Deepened my knowledge in Design Patterns, Hexagonal Architecture, TDD and Agile principles. Strong focus on development best practices: SOLID, YAGNI, KISS and more.

🎓 Education
  • Master's degree in Computer Science — 2021
  • Technical degree (DUT) in Computer Science — 2018
  • High school diploma in Technology (STI2D) — 2016
  • French

    Native or bilingual

  • English

    Fluent

Can work on-site
Belley (up to 20km), Belley (up to 20km), Aix-les-Bains (up to 10km), Chambéry (up to 10km)

Experience

  • Credit Agricole Technologies et Services
    Java software engineer
    BANKING AND INSURANCE
    October 2023 - Today (2 years and 9 months)
    Annecy, France
    I'm part of the Fraud Acquisition team, developing and maintaining a case management platform that allows bank staff to handle fraud dispute cases with customers and decide whether fraudulent transactions should be reimbursed.
    Being in a banking environment means navigating a dense set of regulatory and business rules — which keeps every feature both challenging and meaningful.
    Among the features I delivered:

    • Automated preliminary analysis — the system now automatically evaluates whether a transaction should be reimbursed based on a set of business rules and criteria, removing the need for manual assessment
    • Automated reimbursement — prior to my arrival, the platform was purely declarative. Staff had to manually enter transactions to reimburse in a separate payment tool. I automated this process end-to-end
    • Wire transfer dispute support — dispute handling was initially limited to bank card transactions. I extended the full dispute workflow — from retrieval to analysis and reimbursement — to wire transfers as well
    Java Spring boot Kubernetes Docker JPA/Hibernate
  • Tennaxia
    Fullstack developer
    SOFTWARE PUBLISHING
    August 2022 - October 2023 (1 year and 2 months)
    Lyon, France
    Trackdéchet is a waste management platform used by large companies like Intermarché to track their waste from creation to destruction — whether wooden pallets or radioactive materials. I joined as a fullstack developer, contributing to both the Java/Spring Boot backend and the Vue.js frontend of an existing monolith.
    The highlight of this mission was implementing multi-packaging support within a single transport, a significant feature that required a deep refactoring of the existing data model and had a wide impact across the application.
    What I appreciated most here was the engineering culture. After dealing with legacy codebases in previous missions, this was a refreshing change — the team genuinely cared about code quality. The process reflected that: every feature went through development, peer testing, a merge request reviewed and tested by at least two other developers, a team demo, and a production release only once everything was validated.
    Java Vue.js MySQL Test driven development Hexagonal Architecture
  • CNAF - Caisse nationale d'allocations familiales
    Java software engineer
    PUBLIC SECTOR
    April 2021 - July 2022 (1 year and 4 months)
    Lyon, France
    My first real professional experience in an enterprise environment. I worked on OMEGA, an early childhood grant management software with highly complex business rules — over 250 database tables, a large user base, and years of legacy code to navigate.
    It was a tough but formative environment. Most of the codebase didn't follow modern development practices, which forced me to quickly develop a sense for managing complexity, reading unfamiliar code, and delivering features despite technical debt.
    The highlight of this mission was the opportunity to build a new monolithic application from scratch in Spring Boot — my first hands-on experience with the framework. Going from legacy code to a greenfield project in the same mission gave me a unique perspective on what good software architecture actually means in practice.
    Java Spring boot Hibernate IBM Db2 Scrum

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Education

  • Computer Science Master
    Supinfo
    2021
  • Two-year technical degree (DUT Informatique)
    DUT de Belfort-Montbéliard
    2018

Skill set

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