🔧 Dev

ROIMVP in prod in 30–45 days — without hiring a senior

≈ €75–105k saved over 10 monthsfrom €4,500/ month (≈ 1/3 of a fully loaded senior's cost)

Agents + iASSET gates · dev & cloud included · pipeline live in 1 week

Calculate my ROI

Application developer

Web & mobile apps — Fullstack & DevOps

Technical audit, engineering package or Tech Lead. Mobile MVPs, web and mobile apps with a modern stack and measurable outcomes.

15+ projects+40% perf
GL
Guillaume Lebourgeois
CTO, Adostin

"Jean-Sébastien is an accomplished fullstack engineer: front, back and even DevOps, with a strong infrastructure sensitivity that helped him build a solution close to the highest security standards for health data."

5/5

What I solve for you

Failing architectures, runaway costs, blocked teams — a structured approach changes the game.

Common problems

  • Exploding costs, recurring bugs
  • Disappointing performance, frustrated users
  • Blocked team, unreadable code
  • No path to scale

What you get

  • Cost reduction through an optimized architecture
  • Performance and a properly designed database layer
  • Clean code, documentation, autonomous team
  • Modular, scalable architecture

Technical skills

Modern stack and architecture patterns for web and mobile apps.

Node.js
Backend
TypeScript
Language
React
Frontend
Go
Backend
Python
Language
React Native
Frontend
Next.js
Frontend
Nest.js
Backend
Microservices
Backend
Serverless
Backend
Redis
Cache
PostgreSQL
Database
Docker
DevOps
AWS
Cloud
GraphQL
API

Recent projects

Software engineering work.

Microservices architecture

Microservices for a complaints management application

PythonDockerSwarmPostgreSQL

40% response time reduction, improved scalability and maintainability

Payment gateway API

Development of a multi-provider payment gateway API

Express.jsJWTPrometheusGrafana

Centralized 15+ services, improved security and reliability

Mobile app (healthcare)

Mobile MVP: building a health management mobile app in React Native as a fullstack engineer

React NativeNode.jsDockerPostgreSQL

Improved patient productivity and quality of life

Methodologies

Approaches for robust, scalable systems.

Architecture Driven Development

Architecture-first approach to ensure quality and maintainability

Domain-Driven Design

Model the business domain for a consistent, evolvable architecture

Clean Architecture

Separation of concerns for a maintainable, testable codebase

Security by Design

Integrate security from day one

Value added

What engineering brings to your project.

Performance

Scalability and optimization

Security

Security from the start

Team

Mentoring and training

Scalability

Controlled growth

Packages

Audit, day rate or Tech Lead — depending on your needs.

Architecture audit

2 days

Assessment of your architecture with a report and optimization plan.

  • Full technical audit
  • Report and recommendations
  • Results presentation
Book
Popular

Day rate

1 month min.

Fullstack support: architecture, development, support.

  • 20 days of delivery
  • Architecture & development
  • Documentation

Tech Lead

20 days

Technical leadership, team organization, hiring.

  • Leadership & org
  • Hiring & enablement
  • Technical strategy

Guarantees

Your satisfaction comes first.

Performance

Measurable improvement or refund

Delivery

Commitment on timelines

Satisfaction

Support until you’re satisfied

Ready to move your project forward?

Audit, engineering package or Tech Lead — choose what fits you.

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