You already have an app and want to know what it is really worth.
Audit of your app
excl. VAT · results in a few days€1,200
- I check security, code, data and costs
- A green, amber or red light for each point
- A clear report and a 1-hour video debrief
Jérémy MarquerFractional CTO · France and remote
Fractional CTO and app development
Your tech partner,
from idea to thousands of users.
App development, audits, websites or team leadership: I take care of the technical side of your project. I ship apps and websites, grow them to thousands of users and lead the teams that keep them evolving.
5.0 on Google15 minutes on video, no commitment.
Jérémy MarquerFractional CTO · France and remote
- building and leading tech teams
- 10 years
- registered users on the apps I built
- 150,000+
- people managed in my teams
- 25+
- websites and apps shipped
- 10+
01 / Where to start
Where are you today?
Most clients start with an audit: you know what your app is worth before spending more. Each service has its own page, with its price and examples. The first 15-minute call is free.
You are starting from scratch, or your app needs rebuilding.
Product development
from · excl. VAT€5,000
- Scoping, design, development, launch
- Web app, mobile app or SaaS
- Code and accounts in your name
Your app is growing and your team needs direction.
Fractional CTO
excl. VAT / day€900or €150 excl. VAT / hour
- Roadmap and technical trade-offs
- Hiring and team management
- No mandatory monthly retainer
Other services
- AI & automationfrom €2,500 excl. VAT
- Business websitefrom €2,400 excl. VAT
- AI training or coaching for your team: quoted separately
My projects on TV and in the press
02 / Selected work
Projects I built and led
Companies I co-founded, teams I led and products I built, with their numbers.
Welco
Co-founder · Technical leadershipA collaborative delivery platform, from the product to the engineering team.
- registered users
- 150K
Co-founding, building the technical team, architecture and development of core features.
Explore my contribution
Jo’s Burger
Partner & CTO · Food serviceThe technology behind ordering, payment and delivery.
Formerly Les Burgers de Jo. Mobile app, back office, payment and delivery integration, and process automation.
Explore my contributionEngineering Manager · OncologyResilience Care
Leading two engineering teams working in oncology.
10people managedPersonal product · Mobile appBabyCheckAn app helping parents understand baby food products.
5,766new users in 12 monthsClient work · AI productArchestra.aiFullstack development within an AI product team.
Consulting · Tools & AI assessmentAxiome AvocatsCompared alternatives and a roadmap for the firm’s tools, including AI.
Personal project · EventsMonJoliMariageA SaaS to create an AI-assisted wedding website, manage guests and share moments from the big day.
All projectsWebsites, applications and advisory work.
BabyCheck, with the numbers
My app, launched in 14 days and featured by Apple in December 2025. These screenshots come straight from App Store Connect and RevenueCat.
See the BabyCheck case study
396,000 BabyCheck impressions on the App Store
App Store Connect, since December 2025
An impression is one time the app’s icon and name appear in an App Store list. The December 2025 peak comes from Apple featuring BabyCheck in its weekly selection. Impressions drop afterwards, while monthly recurring revenue keeps rising.
$206 monthly recurring revenue
RevenueCat, on 1 November 2026 · Verified on TrustMRR
Google Reviews
What clients say about working together.
« Jérémy est de très bon conseil. Il nous permet de comprendre des sujets techniques en les abordant de manière pédagogique. »« Un immense merci à Jérémy pour sa réactivité et son professionnalisme. »« Il a su comprendre mes attentes dès le début »Excerpts from Google reviews.
03 / Approach
How I work with you
For every technical choice, you know what it costs and what it risks before deciding. You decide, I deliver.
Analyse before building
Separate the real problem from its symptoms before committing time and budget.
Make decisions and set direction
Build or buy, launch or consolidate: I explain every decision.
Build and lead the team
Hire, organise the work and move product, design and engineering forward together.
Connect vision with execution
A roadmap the whole team understands, and delivery that is tracked.
- 01
Start with the right problem
Your goals, constraints and existing systems. We agree on scope, success criteria and budget before development starts.
- 02
Make progress visible
Short milestones and regular demonstrations give us something concrete to discuss and help us adjust priorities.
- 03
Prepare for what comes next
Documentation, handover and training help you use, maintain and evolve what we have built.
The tools I use
Publishing on the App Store and Google Play, payments with Stripe, data on Firebase or Supabase, AI with OpenAI and Claude.
App Store
Google Play
Stripe
Firebase
Supabase
Flutter
React
Next.js
Node.js
OpenAI
Claude
n8n
Services used in my projects. Trademarks belong to their owners; no commercial partnership.
Welco co-founder and CTO, Jo’s Burger partner and CTO, and Engineering Manager in oncology at Resilience Care: I led these teams from the inside.
Explore the CTO offer04 / Questions
Questions I often get
Another question? Ask me directly: I reply personally.
How much does a fractional CTO cost?
€900 per day or €150 per hour, excluding VAT, with no mandatory monthly retainer. We agree on the time together: a few hours a month for key decisions, or several days a week to lead a team. Product builds start at €5,000 excluding VAT, quoted after scoping.
How is this different from an agency?
You get one point of contact who has led technology in companies and stays accountable for decisions. I can also work alongside your agency or current team: the goal is to clarify direction, not replace everything.
Do you work remotely?
Yes. I am based in Valence, France, and work with companies remotely, travelling when the project needs it.
Who owns the code?
You do. The code, accounts (hosting, database, tools) and documentation are in your name and handed over at the end.
How fast can we launch a first version?
It depends on scope. BabyCheck launched in 14 days; a first SaaS version usually takes a few weeks. Scoping sets the timeline before we start.
How do we get started?
With a free 15-minute call, by video or WhatsApp. I then tell you where to start and what it costs.
05 / Jérémy’s field notes
Field notes
What I build, the decisions I make and lessons you can apply to your business. Product, AI and founder life, with the results and limitations.
Your next step
Let’s talk about your project
An idea to launch, a team to support or a process to simplify? Tell me about your situation and we will work out the next step together.