Sébastien LegrosSeniorfullstack
From the database to the interface. React, Next.js, Go, PostgreSQL. Fully remote from Réunion Island.
I build web products made to last.
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.
10 years of experience, including 6 in development and 3 as lead.
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.
Projects built to be useful, not just attractive
A selection of products and tools where I worked on architecture, experience and production readiness.
Business CRM Platform
Design and development of a complete CRM to centralize prospect management, partner workflows, campaign tracking and business automations.
- React
- Apollo
- Go
- GraphQL
- PostgreSQL
- Docker
- CI/CD
DetailsClose
- Role
- Technical design, data modeling, Go GraphQL APIs, React (Apollo) back-office and third-party service integrations.
- Impact
- A unified platform foundation to track customer cases, automate communication workflows and support multiple operator configurations.
Therapeutic Care Platform
A specialized care platform combining structured content, patient follow-up and domain-specific therapeutic workflows.
- React
- Go
- REST
- PostgreSQL
- Stripe
DetailsClose
- Role
- Full-stack development of the React application, Go REST API, PostgreSQL modeling and overall patient journey structuring.
- Impact
- A clearer tool to manage content, therapeutic goals and patient relationship flows in one coherent place.
Gamification & Campaign Engine
Back-office and APIs to orchestrate game mechanics, subscription plans and reward flows around physical activation triggers.
- React
- Apollo
- Go
- GraphQL
- Stripe
- Wallet
DetailsClose
- Role
- Go GraphQL API design, React (Apollo) back-office, Stripe subscriptions, virtual wallet system and operator-facing management interfaces.
- Impact
- A technical base able to orchestrate campaigns, users, rewards and transactional logic without fragmented tooling.
Mobile Audio Content Platform
GraphQL backend and editorial back-office for a mobile application delivering structured audio content to end users.
- React
- Apollo
- Go
- GraphQL
- Firebase
DetailsClose
- Role
- Model design, GraphQL APIs, React (Apollo) back-office and tooling for content publishing and user management.
- Impact
- A more reliable stack to operate the product, manage content publishing workflows and keep administration straightforward.
More work
Web and back-offices
Automated Editorial PipelineEditorial videos generated automatically, subtitles included.Show description
An automated video editorial pipeline in Go with a Next.js dashboard, Remotion/FFmpeg video rendering, subtitle generation and content orchestration.
- Go
- Next.js
- Remotion
- FFmpeg
Document Management SuiteDocuments and business workflows run from a back-office.Show description
A Go GraphQL API plus React (Apollo) back-office ecosystem to manage documents, business workflows, structured content and admin tooling.
- React
- Apollo
- Go
- GraphQL
Cinema Alert PlatformPersonalised cinema alerts with built-in payments.Show description
A Next.js cinema-focused application with Supabase, Redis, Stripe payments and alert-driven notification logic.
- Next.js
- Supabase
- Redis
- Stripe
Mentora, online English learning platformOnline English lessons with teacher and student spaces.Show description
Teacher and student spaces, step-by-step session builder, results tracking, course material import and export. Next.js, Node.js, TypeScript, Prisma, PostgreSQL, NextAuth.
- Next.js
- Node.js
- Prisma
- PostgreSQL
Preznt (preznt.fr)Interactive digital gifts, payments and 3D scenes.Show description
Interactive digital gift platform: passwordless code sign-in, Stripe payments with webhooks, push notifications, 3D scenes. Next.js 16, React 19, Node.js, PostgreSQL, Stripe, Three.js.
- Next.js
- Node.js
- PostgreSQL
- Stripe
- Three.js
Payments & KYC Back-OfficePayments, KYC verification and reconciliations.Show description
React (Apollo, GraphQL) back-office for MangoPay payment management: payment flows, KYC verification, wallets and reconciliations.
- React
- Apollo
- GraphQL
- MangoPay
VIP Campaign Back-OfficeSMS campaigns and VIP guest management.Show description
React back-office, on a REST API, for SMS campaign management and VIP guest information handling under operational constraints.
- React
- REST
Mobile and data
Guided Podcast PlatformBack-office and backend for a guided podcast mobile app.Show description
React (Apollo, GraphQL) back-office and Go/PostgreSQL backend for a guided podcast mobile app: editorial pipeline, i18n and product logic.
- React
- Apollo
- GraphQL
- Go
- PostgreSQL
SQL Loyalty AnalyticsOptimised SQL queries for a loyalty app.Show description
SQL query optimization and performance work on a mobile loyalty product with complex data models.
- SQL
Accessibility Field AppWheelchair-accessible places, mapped in the field.Show description
Android application to locate wheelchair-accessible places and enrich accessibility field information.
- Android
Interest-Based Matching AppMatching people by shared interests and proximity.Show description
Android app matching people through shared interests and geolocation-based proximity.
- Android
A hybrid profile across web applications, business APIs and desktop software, with a stack built to stay maintainable over time.
Web
React, Next.js, TypeScript, Blazor, C#
React/TypeScript and Next.js interfaces, Blazor back-offices in C#, from component to production.
API & data
Go, Node.js, ASP.NET Core, GraphQL, REST, PostgreSQL, SQL Server
REST and GraphQL APIs in Go, Node.js or ASP.NET Core, on PostgreSQL and SQL Server, clean architecture, solid business logic.
Software
C#, XPO/XAF, DevExpress, WPF, WinForms
Business desktop applications in the .NET ecosystem with productivity-oriented frameworks and rich UI tooling.
A path from infrastructure to product engineering, then technical leadership.
Freelance Developer, Neitsa
New features, maintenance and production releases for a mortgage broker's CRM; design and redesign of websites for independent professionals. React, Next.js, Go, GraphQL, PostgreSQL.
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 and Azure DevOps.
Lead Full-Stack Developer, Squirrel
Fully remote: architecture, full-stack development, GraphQL/REST APIs, data modeling and CI/CD pipelines. Designed and built single-handedly a supporting-documents collection module (rules engine, validation workflow, e-mail/SMS notifications, S3 storage, third-party business software API integration).
Web Developer, Squirrel
Built React interfaces, integrated APIs and grew into product-driven development.
Systems & Networks Administrator, Reunion Region
Infrastructure, security, operations and a strong reliability mindset.
Research Engineer, IRD
Built web and mobile tools for research data collection and visualization.
Computer & Telecommunications Engineering Degree
EducationDUT Networks & Telecommunications
Education
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 opportunities.
slegros9@gmail.com