Where are you based and do you work remotely?

I'm based in Audierne, Brittany (France), and I've worked fully remotely for over 4 years, in professional English and French. Occasional travel is possible.

What kind of engagements do you take on?

Legacy code takeover and refactoring, performance optimisation (SQL, algorithms, APIs) and end-to-end full-stack development — for startups and established groups alike. Time-and-materials or fixed-price, full or part time.

What is your training background?

I trained in Clean Architecture with WealCome and Ancyr Academy, and apply Clean Code, TDD and Domain-Driven Design daily.

Freelance full-stack developer — PHP · Python · TypeScript

Who am I?

I take over the applications nobody wants to touch — and I ship code anyone can pick up after me.

Freelance full-stack developer based in Audierne, Brittany (France). For more than four years I've been designing and evolving applications end to end — PHP or Python on the back, TypeScript (React, SvelteKit) on the front — for startups and established groups alike.

My speciality is the code nobody wants: legacy applications with no documentation, contractors gone overnight, response times going through the roof. I audit, I secure with tests, then I ship clean, tested and documented code — code any developer can pick up after me.

I care about good practices: Clean Code, TDD and Domain-Driven Design. I enjoy optimising and automating processes, and I've been developing with AI since its early days — as a way to accelerate execution, never at the expense of control: I stay in control and lock quality with automated guardrails (linting, tests, CI). I'm the one who guarantees the code I ship.

Away from the keyboard, I surf, spend time by the ocean — an inspiration that even shaped my logo —, listen to and play music, and enjoy video games.

My journey

Yacast — Full-Stack Developer (3 successive engagements — recurring client)
Nov. 2024 → Jul. 2026 · Full remote
Media monitoring solutions — radio/TV music broadcast declarations.
- Rebuild and modernisation of a legacy application: migrating an old Symfony codebase to FastAPI + React.
- Rebuild of the declarations FastAPI backend: more flexible architecture, DocuSign webhook integration.
- React front-end rebuild: forms (React Hook Form), advanced validation with Zod.
- Audit and profiling of a legacy application (PHP/Zend, JS, SQL): reworked SQL queries and algorithms → API response time divided by 10, batches by 3.
Stack : PHP, Zend, Python, FastAPI, React, TypeScript, Zod, SQL, DocuSign API
Skiset — Backend Developer
Feb. 2023 → Feb. 2024 (1 yr) · Full remote
European leader in ski equipment rental. Backend reinforcement on the group's billing apps and CRM/ERP systems.
- Autonomous takeover of a critical billing application (Symfony/React) after the previous contractor left: code study, full documentation, side-effect-free fixes — Sage API integration (Webservice100).
- Reinforcement on a Symfony/EasyAdmin billing app: advanced customisation (search, business views).
- Ongoing maintenance of the group's CRM/ERP (Laminas): AWS S3, SocieteInfo, Lokki integrations; interactive store map; logging.
- SQL query optimisation on high-volume databases.
Stack : PHP, Symfony, EasyAdmin, Laminas, React, SQL, Sage API, AWS S3
Freelance engagements — startups & SMEs — Full-Stack Developer
2025 · Full remote
Varied projects run fully autonomously, from scoping to delivery.
- Management SaaS for dance schools (SvelteKit): Stripe Connect integration, billing.
- Multi-venue music-programming MVP (React + AWS Amplify): event calendar, playlists, real-time administration of Raspberry Pi units.
Stack : SvelteKit, React, AWS Amplify, Stripe Connect
Independent — various projects — Full-Stack Developer
Feb. 2022 → present
Personal builds and varied engagements, fully remote.
- AI image-generation application: FastAPI API (collections, multi-prompt generation), ComfyUI integration, Celery + Redis queuing, real-time SvelteKit front-end.
- B2B store connecting local producers → restaurateurs (Symfony/EasyAdmin): order taking, admin panel, billing dashboard.
- Custom Prestashop modules; admin dashboards (Symfony, EasyAdmin, Remix).
- Legacy takeovers, SQL optimisation and ongoing maintenance.
Stack : Python, FastAPI, Celery, Redis, SvelteKit, Symfony, ComfyUI, TailwindCSS, Prestashop
Sparrow Développement — Full-Stack Developer (freelance, on-site)
Jan. → Sep. 2022 (9 months)
MVP development and legacy takeovers.
- MVP development, mainly on Symfony; legacy takeovers and optimisation.
Stack : Symfony, React
Pack Digital — Full-Stack Developer (agency, employee)
Jan. 2021 → Feb. 2022 (14 months)
First agency experience, working autonomously on Symfony/React projects.
- Complete marketplace: Symfony + API Platform API, React PWA, JWT auth, Stripe integration.
- Centralised multi-site authentication (SSO); a social network for an education project; admin dashboards; Docker; WordPress integrations.
Stack : Symfony, API Platform, React, TailwindCSS, JWT, Stripe, Docker

Skills

Backend

PHP
Symfony
Python
FastAPI
Zend / Laminas
API Platform
Flask

Frontend

TypeScript
React
SvelteKit
Next.js
TailwindCSS
Remix

Data & Perf

SQL optimisation
MySQL / PostgreSQL
Profiling
Redis
Celery

Quality & Craft

Clean Architecture
Automated testing
PHPUnit
pytest
DDD

Ops & Integrations

Docker
CI/CD
AWS S3 / Amplify
Stripe / Connect
Sage
DocuSign
Supabase

Applied AI

AI-assisted development
ComfyUI
Stable Diffusion
LLM API

How I work

Audit before touching

Profiling and understanding the domain before making any change.

Secure with tests

Automated tests and systematic regression checks on legacy code.

Ship something maintainable

Documented code, clear architecture — any developer should be able to pick up after me.

AI, kept under control

A way to accelerate execution and get up to speed on an unfamiliar codebase — under human control and tooled guardrails (linting, tests, CI) over all the code shipped.

Fully autonomous, remote

For 4 years: scoping, proactive communication, end-to-end project management.

Away from the code

Surfing & the ocean
Music (listening & playing)
Video games
Tech & AI

What clients say

Corentin worked with us for over a year and showed consistent professionalism. A great listener, he knew how to work as part of a team. Corentin played an active role in building and maintaining robust software solutions. His ability to understand the project's specific needs was a valuable asset for our team. What sets Corentin apart is his intellectual curiosity and constant drive to learn and improve. His ability to quickly adapt to new environments and effectively solve complex problems reflects his versatility and agility as a developer.

Michel ValenzaCIO · Skiset

Corentin threw himself passionately into the assignments he was given. He showed energy and perseverance to build up his skills whenever it was needed. I wouldn't hesitate to call on his growing expertise again during peaks of activity.

Vincent BrayCEO · Agence Sparrow

Corentin played a key role in optimising our application's performance, improving response times through an effective overhaul of the SQL queries and the PHP, JavaScript and Python code. His responsiveness, professionalism and attention to detail make him a valuable collaborator. Always attentive to our needs, he proposed suitable and lasting solutions. We highly recommend him for any assignment requiring a skilled and committed full-stack developer.

Christophe BaillonCTO · Yacast

Frequently asked questions

Ride the digital wave

An application to take over, legacy to evolve, an API to optimise? Drop me a line — I reply fast.

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