Sébastien Legros | Full-Stack Developer & Software Engineer

SébastienLegros

Full StackWeb & software developer

Today I design both web applications and business software. Frontend, backend, desktop and data: React, Blazor,Golang, C#, WPF, WinForms, DevExpress, SQL Server,PostgreSQL, XAF/XPO and robust application architecture.

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An approach shaped by clarity, product thinking and execution

I favor systems that stay easy to evolve, interfaces that stay readable, and technical decisions that genuinely support the product.

I enjoy building real-world web applications and business desktop software: back-offices, SaaS platforms, custom C# applications, APIs, payment flows, content systems, integrations and internal tools. My goal is to turn a fuzzy need into something usable, stable and clean to maintain over time.

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Design the right thing

I start from the actual need, the user flow and the business constraints before committing to implementation details.

Build it cleanly

Structure, naming, controlled technical debt and codebases the team can pick up without friction matter a lot to me.

Ship with confidence

CI/CD, Docker, APIs, perceived quality and interface polish: the finish matters as much as the feature itself.

Selected work

Projects built to be useful, not just attractive

A selection of products and tools where I worked on architecture, experience and production readiness.

eConnect CRM

Design and development of a complete CRM used to manage prospects, partners, campaigns and business automations.

ReactGoGraphQLPostgreSQL

Role: Technical design, estimation, data modeling, Go GraphQL APIs, React interfaces and third-party integrations.
Impact: A centralized product foundation to track cases, automate communication workflows and support multiple white-label variants.

Begaiement

A speech therapy platform combining content, patient follow-up and product-specific workflows.

ReactGoRESTPostgreSQL

Role: Full-stack development of the React application, Go REST API, PostgreSQL modeling and overall journey structuring.
Impact: A clearer tool to manage content, therapeutic goals and patient relationship flows in one place.

QR Win

Back-office and APIs to run game mechanics, subscriptions and reward flows around QR code activations.

ReactGoRESTStripe

Role: Go API design, admin tooling, Stripe subscriptions, virtual wallets and operator-facing interfaces.
Impact: A technical base able to orchestrate campaigns, users, rewards and transactional logic without fragmented tools.

Happiz

GraphQL backend and editorial back-office for a mobile audio content application.

ReactGoGraphQLMobile backend

Role: Model design, GraphQL APIs, administration interfaces and tooling for content and user management.
Impact: A more reliable stack to operate the product, manage content publishing and keep administration straightforward.

More work

ActuFlux

An automated editorial pipeline in Go with a Next.js dashboard, Remotion/FFmpeg video rendering, subtitles and content orchestration.

Prelys Suite

A Go API plus React back-office ecosystem used to manage documents, business workflows, content and admin tooling.

CineActu

A Next.js cinema-focused application with Supabase, Redis, Stripe payments and alert-driven product logic.

E-learning English

A learning platform built with Next.js, Prisma/PostgreSQL, rich interfaces, content import flows and AI-assisted features.

Leon

Guided podcast app with APIs, i18n, editorial pipeline and mobile product logic.

Raoul

Web application for MangoPay-based payment management with flows, KYC, wallets and reconciliations.

PSG VIP

Back-office for SMS campaigns and guest information management under operational constraints.

Fidelatoo

SQL query work and optimization on a mobile loyalty product.

Handimobi

Android application to locate wheelchair-accessible places and enrich field information.

Ladar

Android app matching people through shared interests and geolocation.

Expertise

A hybrid profile across web applications, business APIs and desktop software, with a stack built to stay maintainable over time.

Web

Modern, readable and maintainable web interfaces for product and back-office use cases.

React
Blazor

API & data

Robust APIs, clear business logic and structured SQL databases for reliable applications.

Golang
PostgreSQL
SQL Server

Software

Business desktop applications in the .NET ecosystem with productivity-oriented frameworks and rich UI tooling.

C#
XPO/XAF
DevExpress
WPF
WinForms

Background

A path from infrastructure to product engineering, then technical leadership.

Education

2010 - 2012

DUT Networks & Telecommunications

Education

2010 - 2012

DUT Networks & Telecommunications

2010

Education

2012 - 2015

Computer & Telecommunications Engineering Degree

2012

Education

2012 - 2015

Computer & Telecommunications Engineering Degree

Work

2016 – 2017

Research Engineer — IRD

Built web and mobile tools for research data collection and visualization.

Work

2016 – 2017

Research Engineer — IRD

Built web and mobile tools for research data collection and visualization.

2016

Work

2017 – 2021

Systems & Networks Administrator — Reunion Region

Infrastructure, security, operations and a strong reliability mindset.

2017

Work

2017 – 2021

Systems & Networks Administrator — Reunion Region

Infrastructure, security, operations and a strong reliability mindset.

Work

2021 – 2022

Web Developer — Squirrel

Built React interfaces, integrated APIs and grew into product-driven development.

Work

2021 – 2022

Web Developer — Squirrel

Built React interfaces, integrated APIs and grew into product-driven development.

2021

Work

2022 – 2025

Software Engineer / Lead Web Developer — Squirrel

Architecture, full-stack development, GraphQL/REST APIs, data modeling and CI/CD pipelines.

2022

Work

2022 – 2025

Software Engineer / Lead Web Developer — Squirrel

Architecture, full-stack development, GraphQL/REST APIs, data modeling and CI/CD pipelines.

Work

2026 – aujourd'hui

Software Designer & Developer — Willow

Design and development of web and business applications with C#, MVVM, WPF, WinForms, DevExpress and Blazor, powered by SQL Server, XAF/XPO, Azure AI and Azure DevOps.

Work

2026 – aujourd'hui

Software Designer & Developer — Willow

Design and development of web and business applications with C#, MVVM, WPF, WinForms, DevExpress and Blazor, powered by SQL Server, XAF/XPO, Azure AI and Azure DevOps.

2026

Contact

Need to structure, ship or strengthen a product?

I can help on an existing product, a technical foundation that needs to be stabilized, or a new initiative that should start cleanly.

Open to freelance work

slegros9@gmail.com LinkedIn

Or directly by email slegros9@gmail.com