Product Founding Engineer
You have an app idea.
I ship the whole thing.
From a sketch to a launched product: design, backend, infrastructure and AI, built end to end by one senior engineer. EU-based, GDPR-first.
The brief
One idea, shipped as a complete product
A personal trainer came to me with a gym, a whiteboard, and a lot of evenings lost to admin. What follows is the platform I designed and built for them, end to end. Forty-five seconds:
The whiteboard problem
Every plan was being written twice
Before
Workouts went up on the gym whiteboard during the day, then got typed into a computer again at night. The same work, done twice, for hours every week after the gym had closed.
After
Now they photograph the board on their way out. The handwriting is read and turned into a structured plan, and it lands on their clients' phones before they have reached the car park. The app installs straight to their home screen like any other. No app store, no download.
Knowing who needs you
From forty check-in texts to one screen
Before
Checking in meant messaging clients one at a time and hoping for an honest answer. The people quietly falling behind were the same people who stopped replying.
After
One overview shows who is overdue, who is slipping, and who is on track. Their attention goes to the four people who need them this week, instead of being spread thin across forty who mostly do not.
Handling the sensitive part
Nutrition data that stays between two people
Clients share their nutrition numbers only if they choose to, and can withdraw at any time. Everything sits in an encrypted European database that only their own coach can open. When the AI reads a screenshot to pull the numbers out, it never learns whose numbers they are. The name is attached afterwards, in a separate scripted step the model plays no part in.
Where it all runs
Everything stays in the EU
Hosting, database, backups and the AI itself all run on European infrastructure. Nothing crosses the Atlantic. GDPR shaped it from the first line of code.
The work
What "end to end" actually means
No handoffs, no gaps between design and engineering. One person across the whole stack.
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Design & UX
Product flows, interface, brand.
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Frontend
Fast, accessible, responsive web apps.
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Backend & APIs
Business logic, integrations, jobs.
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Database
Modelling, migrations, performance.
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Infra & DevOps
Deploys, CI/CD, EU hosting.
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AI integration
Language models on sovereign, EU-hosted infrastructure.
- Next.js
- FastAPI
- PostgreSQL
- Scaleway (EU)
- Mistral (EU AI)
- Docker
The process
Idea to shipped, in weeks
- 01
Idea
You bring the vision. We pin down what to build.
- 02
Scope
A tight, shippable first version. No bloat.
- 03
Build
Design, backend, infra and AI, in one pair of hands.
- 04
Ship
A real product, launched and yours.
Who builds it
Crystallized Intelligence
An AI consultancy in Luxembourg run by Aisling McCaffrey. EU-based and GDPR-first by default, so your data and your users' data stay on sovereign, EU-hosted infrastructure. When you need one senior person to take an idea all the way to a launched product, that's the work.
Make your vision a reality.
Tell me about your idea. I'll tell you how I'd ship it.