5.0 on Trustpilot

You build the product with AI.
I make sure it is
solid

Your product is production-ready: the important parts work, people can sign up, pay, and use it without things breaking.

Launch readiness. Future proof.Critical user flows. Ready for scale.Ongoing technical support. 6 days a week.

11+ years

shipping production software

2-4 weeks

to stabilize the core product

1 technical partner

who keeps things clear and practical

I've worked with

CMA CGM
Pellenc ST
Squad
Circlée
Cocolis
This is Blindtest
Doxa
2S Computing
XBTO
BPCE
Crédit Agricole
Solent
CMA CGM
Pellenc ST
Squad
Circlée
Cocolis
This is Blindtest
Doxa
2S Computing
XBTO
BPCE
Crédit Agricole
Solent

The gap

AI tools build features. But who builds the foundation?

Cursor, Bolt, and Claude Code can move fast. They do not give you a reliable product, a calm launch process, or a plan for when things get messy.

What changes

You should not have to learn DevOps just to ship your product.

My job is to turn your AI-built product into something that can handle real users, real growth, and real change without becoming chaos.

No clear structureARCH

No clear structure

The product grew quickly, but nobody defined how it should stay organized. Every new change adds more mess.

No safety netSAFE

No safety net

There are no reliable checks before launch. Problems show up in front of customers instead of being caught early.

No reliable launch setupOPS

No reliable launch setup

The app is live, but there is no safe place to test, no clear alerts, and no fallback when something breaks.

No maintenance planCARE

No maintenance plan

Small issues pile up quietly until they become expensive problems that slow everything down.

Process

Three steps from idea to production

The goal is simple: keep the speed of AI-assisted building without ending up with a product you are afraid to launch.

Discovery

I look at what you are building, where it feels fragile, and what needs to be fixed first. You leave with a clear plan.

Setup

I set up the parts behind the product that founders should not have to figure out alone, so launch feels safer and the product is easier to trust.

Build and maintain

You keep building features with AI. I keep the product healthy, answer the hard questions, and help when growth adds complexity.

Deliverables

Everything you need to ship. Nothing you do not.

This is not vague advice. You get the pieces that make an AI-built product feel stable, launchable, and easier to grow.

Architecture that scalesCORE

Architecture that scales

A product setup that stays understandable as it grows instead of getting harder to work with every week.

  • You and your AI tools work inside clear patterns
  • New features create less cleanup later
  • You know where things belong as the product evolves
Signups that workAUTH

Signups that work

The core user flows people expect are handled properly from the start.

  • Login, signup, and password reset are in place
  • Protected areas and sensible access rules are handled
  • Less risk of fragile workarounds around user access
Data you can trustDATA

Data you can trust

Your product data has a clean foundation instead of a pile of shortcuts.

  • The structure matches how your business actually works
  • Changes can happen safely as the product grows
  • Future updates are less scary and less brittle
Safer launchesSHIP

Safer launches

Changes are checked before customers see them, not after something breaks.

  • Problems are caught earlier instead of in production
  • There is a better path from testing to going live
  • Launch day comes with fewer surprises
Visibility and maintenanceWATCH

Visibility and maintenance

You know when something goes wrong, and there is a plan to keep the product healthy.

  • You hear about issues before they become customer complaints
  • Updates and maintenance do not get ignored
  • Less firefighting and fewer surprise problems over time
AI that keeps helpingAI

AI that keeps helping

Your tools stay useful because they are working inside a better system.

  • Clear rules keep AI-generated work aligned
  • Repeatable workflows make common tasks easier
  • You move faster with less rework and less drift

Pricing

Choose your starting point

The scope changes with your product. The outcome stays the same: you get something you can launch and keep building without constant tech anxiety.

Know where you stand

Audit

1 500 €

I review your product top to bottom and tell you exactly what is risky, what is solid, and what to fix first. Fundraising? Use the report to show investors your tech is solid.

Turnaround

~3 days

Full codebase review covering security, data, auth, and deployment
A written report with prioritized findings and clear next steps
Technical due diligence report you can share with investors
A one-hour walkthrough call to go through everything together
Actionable recommendations you or your AI tools can follow

Optional add-on

+200 €

Quick security scan

Pentest by a certified partner to spot exposed secrets and common OWASP issues.

Launch ready

Most popular

5 000 €

10 000 €

I set up the critical parts of your product so you can launch with confidence, auth, data, done right.

Turnaround

~2 weeks

Auth and data layer configured inside your product
Your AI workflow cleaned up so it stops creating debt
A clear structure you and your AI tools can keep building on
I deploy everything to production, you launch, not babysit
One onboarding session so you understand every change I made
1 month of Active maintenance included after launch

Optional add-on

+200 €

Quick security scan

Pentest by a certified partner to spot exposed secrets and common OWASP issues.

Maintenance retainer

Optional

Stay healthy after launch.

Your first month on the Active plan is included with every Stack. After that, pick the level that fits.

Light

800 €/month

Async support, monitoring, and dependency updates. For founders who mostly build alone but want a safety net.

Get started

Active

1 500 €/month

Everything in Light, plus code reviews and a monthly check-in. For founders shipping fast who want hands-on guidance.

Get started
Khor

About

The foundation is the gap between prototype and product.

I help founders turn fast-moving AI-built products into products they can actually trust with real users.

For the last 11+ years, I have built the parts most customers never see but always feel when they are missing. For 5 years, I built my own SaaS products, in the restaurant industry and customer review management, and in 2023, I developed an AI orchestration technology for software development, well before these tools went mainstream.

I started Vibengineer because AI changed who gets to build software. Founders can move faster than ever, but the gap between a prototype and a real product is still very real. You stay in control of the idea and the features. I make sure the product underneath can support that speed.

— Sébastien

6 SaaS

shipped solo, 5 of them before AI tools

With your AI

works with the tools you already use

11+

years of production experience

Hands-on

setup, rescue, and ongoing support

Expertise

LaunchesRescuesSaaS productsMarketplacesSubscriptionsFounder enablementAI workflowsOngoing maintenance

Security partner

Antoine Heriaud

Antoine Heriaud

Certified pentester — Cybreach Consulting

Security scan available as an option inside my packages, so your product doesn't leak data or access.

Verified reviews

They've worked with me

Real feedback from clients and peers, verifiable on Trustpilot and LinkedIn.

Trustpilot
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

Jon Mandel

Doxa Formation, training organisation

Verified review on Trustpilot
LinkedIn
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

Sébastien Fieloux

Freelance Ruby on Rails / Magento 2

Recommendation on LinkedIn
LinkedIn
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

Ariane Spanneut

Full Stack Engineer, ex-Coding Factory Squad

Recommendation on LinkedIn

FAQ

Questions founders usually ask before booking

vibengineer
Me contacter

Hier 14:04

What tech stack do you use?

I usually use a modern web stack that is reliable, fast to build on, and well suited to SaaS-style products. On the call, I will recommend the right setup for your product and explain the tradeoffs in plain English.

Hier 14:06

I already started building with AI. Can you work with my existing code?

Often, yes. The discovery call is where I assess whether your current codebase can be rescued cleanly or whether a new foundation will save you time and money.

Hier 14:09

Do I need technical knowledge to work with you?

No. The point is to remove that burden. I handle the engineering foundation and teach you how to keep building inside it with AI.

Hier 14:12

What happens after the stack is set up?

You keep building features. I keep the product healthy, handle maintenance, and help when technical decisions get harder as the product grows.

Hier 14:15

How is this different from hiring an agency?

An agency usually builds the product for you. I build the system that lets you keep building the product yourself without depending on someone else for every feature.

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Ready to launch

Stop worrying about the tech. Start shipping your product.

Book a free 30-minute discovery call. I will assess your current setup, show you the main risks, and recommend the right stack for your stage. No obligation.

Book your free discovery callLimited to 5 new stacks per month

Your idea stays confidential. Always.

Vibengineer | Your AI-Built Product, Made Production-Ready