From zero
to one.
I build companies, not just code. Serial founder with a PhD who also does positioning, sales decks, cold outreach, and fundraising.
I help early-stage startups find their market, craft the story, and ship the product. All at once. Based in Belgium, building across Europe.
The Problem
Going from zero to one is the hardest part. You don’t just need someone who can code. You need someone who can figure out what to build, for whom, and why they’ll pay for it.
Most technical hires can’t do market research. Most marketers can’t ship product. You need someone who does both. Someone who understands the technology deeply enough to architect it right. And understands the market well enough to make sure it matters.
Hiring a co-founder takes months and equity. Agencies don’t have skin in the game.
This isn’t consulting. No slide decks that sit in a drawer. No discovery phases. I build alongside you. If it needs to be coded, I code it. If it needs to be sold, I sell it.
— Willem
Track Record
I’ve been starting companies and shipping products for over a decade. The kind where you do everything. Write the code. Close the first customers. Raise the money.
Serial founder
e-invoice.be, SevenYoken.ai, Airobi.ai, Elimity. From blank page to product-market fit, every time.
PhD in Computer Science
KU Leuven, Belgium. Specialized in secure software engineering.
Self-taught in sales & marketing
Market research, competitive analysis, positioning, cold outreach. Learned by doing, not by reading.
Raised 800k seed
Grew Elimity from concept to scale-up to acquisition in the European identity governance market. Pitched, closed, hired, built.
Engagements
Co-Builder
€8,000/moEmbedded part-time in your startup. I work across product, tech, and go-to-market. Whatever the bottleneck is that week. Roughly 8 hours per week.
Product Sprint
€10–20KTime-boxed 1–2 week deep dive. Ship an MVP, validate a market, nail your positioning, or architect your platform.
Advisory
€2,000/dayStrategic sessions on demand. Technical due diligence, market analysis, fundraising prep, or hiring your first engineers.
I work across market research, product strategy, positioning & go-to-market, AI/ML pipelines, security architecture & compliance, EU regulatory strategy (AI Act, GDPR, DORA), enterprise APIs, cloud infrastructure, e-invoicing & Peppol, fundraising, and technical due diligence.
Ventures
SevenYoken.ai
2026–presentCo-Founder
Autonomous accounting for European SMEs. AI agents that handle bookkeeping end-to-end. Forward an invoice, it gets booked.
e-invoice.be
2025–presentCo-Founder
E-invoicing platform. Peppol certified access point and service provider.
Airobi.ai
2023–2024Co-Founder
Customer service automation built on top of Trengo. AI-powered support agents for e-commerce.
Elimity
2017–2022Co-Founder & CEO
Identity governance & analytics for complex enterprises. Raised 800k seed, built the product and team from zero.
Plus several others I’m not at liberty to disclose publicly. Happy to share more on a call.
Fit Check
Good fit
- You’re pre-product or pre-PMF and need to build
- You have a market thesis but no technical co-founder
- You want someone in the trenches, not on the sidelines
- Speed matters. You want to ship in weeks, not months
- You’re building in or for the European market and regulation matters
Not a fit
- You want a strategy deck without execution
- You’re looking for a staff augmentation agency
- Your product is at scale and you need a full-time CTO
- You want someone who just codes what they’re told
Questions
What does a co-builder actually do?
Everything a technical co-founder would do, without the equity conversation. I write code, do market research, build the pitch deck, close the first customers. Whatever the bottleneck is that week.
I have an idea but no product. Where do we start?
Market validation first. We figure out who pays and why before writing a line of code. Then we build the smallest thing that tests the thesis. A Product Sprint gets you from idea to working prototype in 1–2 weeks.
I already have tech. Can you help reposition it for a different market?
Yes. Same technology, different positioning, different buyer. I help identify the new market, reshape the story, and adapt the product where needed. Sometimes the biggest pivot is in messaging, not in code.
How fast can we get to a working prototype?
A Product Sprint runs 1–2 weeks. You get a working prototype, not a mockup. I scope aggressively so we ship something real, fast.
We’re fundraising. Can you help with the technical risk story?
I help you frame the technical narrative investors need to hear. Architecture decisions, scalability plan, build-vs-buy rationale, and the risks you’ve already mitigated. I’ve raised capital myself, so I know what they’re looking for.
An investor wants technical due diligence. Can you run it?
Yes. I review architecture, codebase, infrastructure, security posture, and team capability. You get a clear report with findings, risks, and recommendations. I’ve been on both sides of this process.
We have legacy code and tech debt. Is that something you handle?
I assess what’s worth saving and what needs rebuilding. Then we plan the migration in phases so you’re not stuck in a rewrite that never ships. Pragmatic cleanup, not perfectionism.
How is this different from hiring a fractional CTO?
A fractional CTO advises. I build. I write code, ship features, talk to customers, and do the work. Think of it as a technical co-founder on a monthly retainer, not a consultant who shows up for a few hours.
Let’s talk.
Building something and need a partner who works across the full stack? Tech, product, and market.