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Jonathan C.JC

Jonathan C.

Senior Backend Developer | Symfony APIs + AI

On-demand
Toulouse, FR
8-15 years

Average response time: 1 hour

Freelancer profile translated to English.
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About Jonathan

I develop backend and fullstack solutions for positive impact scale-ups: energy transition, e-health, tech innovation.

My approach: understand the real need before coding, then build sustainable solutions (no quick & dirty). I take the necessary time to do things right.

WHAT I DO

I design robust backend APIs and frontend interfaces depending on the projects. Complete vision: from user needs to technical infrastructure.

PROJECTS COMPLETED

🔋 IES Synergy (Electric Mobility - 2 years)
Creation of an API Platform foundation for managing charging station fleets. Setup of a complete Docker development environment + CI/CD.
Stack: PHP 8, Symfony 6, API Platform, Docker, PostgreSQL

🏡 Cozynergy (Energy Renovation - 9 months)
Overhaul of the energy diagnosis simulator with integration of an external AI engine. Admin interface (EasyAdmin) for platform management.
Stack: PHP 8, Symfony 6, EasyAdmin, GraphQL, Third-party AI API

📱 Free Mobile (Telecoms - 9 months)
Development of encrypted JWT authentication OpenSSL for REST API accessible from the mobile application (millions of Iliad.it users).
Stack: PHP 7, Symfony 5, JWT, OpenSSL, MySQL

🏥 ADMR (E-health - 1 year)
Implementation of INS (National Health Identity) within the health ERP on a custom PHP framework.
Stack: PHP 7.4, MariaDB, Angular

TECHNICAL EXPERTISE

Backend (confirmed mastery):
• PHP 8 / Symfony 5-6-7
• API Platform, Docker, PostgreSQL, MariaDB
• JWT, OpenSSL, CI/CD (GitHub Actions)

Frontend (depending on project needs):
• React, Next.js, Angular

Learning in progress (2025):
Python, LLM, RAG, ontology, PayloadCMS

WHO I WORK FOR

Positive impact scale-ups that need to:
→ Develop a solid backend API (Symfony, API Platform)
→ Integrate AI services (Third-party APIs, LLM)
→ Improve code quality (tests, documentation)
→ Train their teams
  • French

    Native or bilingual

  • English

    Conversational

  • Spanish

    Basic

Can work on-site
Toulouse (up to 50km)

Experience

  • Cozynergy
    Backend Development Engineer
    ENERGY AND UTILITIES
    November 2024 - July 2025 (8 months)
    Toulouse, France
    Overhaul of the energy renovation simulator: the objective of the overhaul is to create a white-label simulator and replace the historical calculation engine with one based on Artificial Intelligence (Kelvin).

    o Analysis of the historical simulator and the impacts of the overhaul
    o Adaptation of the existing workflow
    o Integration of the new calculation engine
    o Setup of the new project
    o Data modeling
    o Creation of an administration interface via EasyAdmin
    o Realization of a GraphQL API
    Symfony PostgreSQL GraphQL EasyAdmin Kubernetes
  • Free Mobile
    Symfony Backend Developer
    TELECOMMUNICATIONS
    May 2024 - October 2024 (5 months)
    Montpellier, France
    Intervention on a Symfony REST API for the creation of a mobile application for iliad.it mobile subscribers

    o Addition of business features around the subscriber (authentication, password change/reset, user information retrieval/update, plan options management)
    o Overhaul of the subscriber authentication system via Access Token (JWT + OpenSSL encryption)
    o Needs analysis / documentation writing
    o Reverse engineering and migration of historical code
    o Setup of the missing Docker part to fully launch the project locally via Docker (creation of a custom Docker image)
    o Capitalization of unit-tested generic code
    o Optimization of the Merge Request process (code review, labels to manage MR status)
    o Improvement of functional test content (data and structure verification complementing initial success or failure checks)
    Docker Symfony REST MySQL JWT
  • IES SYNERGY
    Full-Stack Developer
    AUTOMOBILE
    March 2022 - March 2024 (2 years)
    Montpellier, France
    Development "From Scratch" of a B2B Web application for managing an electric vehicle charging station fleet.

    o Setup of a Docker backend development foundation (API Platform, MySQL, PHP Unit, Mercure, Mail Catcher)
    o Setup of an Ionic / Angular frontend development foundation
    o Centralization of documentation in a Redmine wiki
    o Definition of development conventions and best practices
    o Optimization of Merge Request processes (Code Review, weekly Pair Review, "commit messages" convention, Merge Request Template)
    o Development of essential components for communication with existing APIs
    o Setup of a "Real-Time" communication system using Server Sent Events via Mercure (alternative to websockets)
    o Participation with the UI/UX Design provider (Persona, User Journey, technical feedback)
    o Watch (monitoring and migration of project technologies, writing acquired knowledge in the centralized wiki, performing "Proof of Concept")
    o Setup of a Python / Pandas foundation that allows generating usage reports for the park (Excel) in the background or daily communicating energy consumption readings for the charging stations as part of the TIRUERT law.
    Symfony API Platform Angular Docker Python

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Education

  • Master ILSEN (Software Engineering for the Digital Society)
    CENTRE D'ENSEIGNEMENT ET DE RECHERCHE EN INFORMATIQUE - Avignon
    2018
    https://ceri.univ-avignon.fr/formations/master-informatique/master-informatique-7004.kjsp
  • Professional Bachelor's degree in Computer Systems and Software Development and Administration of Internet and Intranet
    Aix-Marseille Université
    2016
    https://iut.univ-amu.fr/diplomes/licence-professionnelle-application-developpement-web-bigdata-ecommerce

Certifications

  • Digital Marketing Fundamentals Certification
    Google Digital Active
    2016

Skill set (33)

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