You run the business.
I take care of the
tech
12 years
shipping production software
2-12 weeks
from idea to live product
1 single partner
from scoping to maintenance
I've worked with
Products delivered, running in production.
From CMA CGM to startups, the same standard: ship a reliable and robust product, used by real users.
Maritime transport · Logistics
Frontend lead on a cargo route planning application, used daily by planning teams.
700,000
users
Marketplace
Built the card payment system at the heart of the platform's order flow.
Food service · SaaS
Built a full online ordering SaaS from scratch, from the first screen to production.
AZ
from idea to production
The business is moving. The tech has to keep up.
The product has stalled, bugs are piling up, and maintenance falls on no one. You are missing someone to handle the tech.
No technical team
The idea is clear, the market responds, but nobody is building. Every week without a product is a week lost.
A prototype running out of steam
Lovable, Bolt, or Cursor validated the idea. Now that real customers are arriving, things break, and nobody knows why.
Tech is eating your time
You spend your evenings debugging instead of selling. It is not your job, and it shows in your growth.
Nobody to maintain it
No monitoring, no alerts, no plan. Every outage becomes an emergency you handle alone.
You delegate the tech to a single partner. You stay focused on your customers.
I take full responsibility for the product: scoping, development, deployment, and maintenance. You validate the decisions, I deliver the rest.
Three steps from idea to production
You always know where things stand, what it costs, and what comes next.
Scoping
A discovery call, then a precise scope: features, timeline, and a fixed-price quote within 48 hours. For a takeover, I audit the existing product first.
48 h
for a fixed-price quote
Build
I design and develop the full product: front end, back end, auth, payments, integrations. You see progress every week.
Launch and maintenance
I deploy to production on your accounts, walk you through everything, and stay available for fixes and new features.
A real product in production. Not a prototype.
Everything a prototype lacks to hold up in production: architecture, security, deployment, monitoring.
A solid architecture
Foundations built to last and evolve with your product.
- A clear structure any developer can pick up
- New features slot in without breaking things
- Less technical debt as the product grows
A reliable path to production
Changes are checked before your customers ever see them.
- CI/CD pipeline: automatic tests, builds, and deployments
- A staging environment before every release
- Hosting configured on your accounts
adminstaffuserAuth and user accounts
The essential flows handled properly from day one.
- Login, signup, and password reset in place
- Consistent roles and permissions
- Protected areas and reliable access rules
Data kept secure
A structured database that follows your business without breaking.
- The structure matches how your business actually works
- Schema changes happen safely
- Backups and migrations handled cleanly
liveMonitoring and maintenance
You know when something is wrong, and someone takes care of it.
- Alerts before your customers notice a problem
- Updates and dependencies tracked over time
- A clear plan when an incident happens
AI as an accelerator
I build with the best AI tools, guided by 12 years of craft.
- 01
Short timelines without sacrificing quality
- 02
Code that is reviewed, tested, and maintainable, not blindly generated
- 03
Controlled prices thanks to development speed
Choose your offer
An audit to know where you stand, a takeover if your product already exists, a full build if it still needs to be built. In every case: a fixed-price quote within 48 hours after the discovery call.
Maintenance retainer
No commitmentStay healthy after launch.
Your first month on the Active plan is included with every takeover or build. After that, pick the level that fits, cancel anytime.
Light
800 €/month
Async support, monitoring, and dependency updates. The safety net for a stable product that changes little.
Get startedActive
1 500 €/month
Everything in Light, plus product changes and a monthly check-in. For products that move every month.
Get started
Architecture is the gap between prototype and product.
I help founders and teams go from idea, or prototype, to a production product they can actually trust.
A software engineer for the last 12 years, I have built products used in production. For 5 years, I built my own SaaS products, in the restaurant industry and customer review management, designing every screen and every user flow myself. That is where I forged a product and UI/UX culture that makes the difference: a good product is not just solid code, it is an interface your customers understand in three seconds. In 2023, I developed an AI orchestration technology for software development, well before these tools went mainstream.
I created Vibengineer because AI changed how fast software can be delivered. Used well, it lets me ship custom products on timelines and prices an agency cannot match. Used badly, it produces fragile prototypes. The difference comes down to expertise.
Sébastien V.
12
years of production experience
6 SaaS
shipped solo, 5 of them before AI tools
AI pioneer
AI orchestration for development since 2023
Hands-on
builds, takeovers, and ongoing support
Expertise
Security partner
Antoine Heriaud
Certified pentester — Cybreach Consulting
Security scan available as an add-on in my offers, to make sure your product does not leak data or access.
They've worked with me
Real feedback from clients and peers, verifiable on Trustpilot and LinkedIn.
“Sébastien is extremely efficient and rigorous. The project was led with great clarity and excellent structure. The work delivered is of very high quality. I will work with him again without hesitation on my next projects.”
Jon Mandel
Doxa Formation, training organisation
“I had the chance to work with Sébastien for a whole year on one of our major projects. He joined one of our teams, and the first things that stood out: he is very professional and integrates perfectly! […] He was at once a teammate, a collaborator, and an experienced consultant, an expert in his technologies.”
Johan Barbier
Head of Digital Solutions Engineering & Industrialisation, Pellenc ST
“Sébastien is experienced, very curious and a great listener. His feedback as a freelance also helped me approach projects differently. I really enjoyed working alongside him and recommend him without hesitation.”
Ariane Spanneut
Full Stack Engineer, ex-Coding Factory Squad
“I had the chance to work with Sébastien on a React/Next.js application, and everything went extremely well. Available, friendly and skilled, Sébastien has all the qualities to help you out!”
Sébastien Fieloux
Freelance Ruby on Rails / Magento 2
Questions I get asked a lot
Ready to delegate?
Stop worrying about the tech. Focus on your customers.
Book a free 30-minute discovery call. We scope your project or your existing product, and you get a fixed-price quote within 48 hours. No commitment.
Your idea stays confidential.