Fractional CTO & AI Engineer
20+ years building and scaling AI-driven platforms. Ex-YC founder, now helping startups and scale-ups ship production AI, build engineering teams, and get the technical side right for investors.
About Me
I've been building software for over twenty years, from a Y Combinator startup in Silicon Valley to fractional CTO roles across Amsterdam and beyond. Most of that time has been spent on the hard part: turning AI and data into systems that actually work in production, not just in demos. I care about architecture that scales, security that's built in from day one, and shipping things that users depend on.
At Kilo Code I helped scale an AI coding assistant processing over a trillion tokens per week. At Bottlenose I built real-time social analytics pipelines from scratch. The pattern is the same: take something complex, bring structure to it, and ship.
Hands-on where it matters, strategic where it counts.
AI & ML Architecture
RAG pipelines, agentic AI systems, LLM lifecycle management. The focus is always the same: getting AI past the demo and into production.
Platform Engineering
Scalable data-intensive platforms, cloud infrastructure (AWS, Azure), and security-first system design from prototype to production.
Engineering Leadership
Building and scaling engineering teams, setting technical direction, and being the person founders put in front of investors when the questions get technical.
Security & Compliance
Security-first architecture, regulatory compliance in domains like healthcare and legal, DPO responsibilities, and enterprise-grade systems.
Services
From hands-on engineering to strategic leadership, I help startups and scale-ups build the right thing and ship it.
My Approach
How I build software, the tools I rely on, and the principles behind my infrastructure choices.
Projects
A selection of recent projects where I led engineering, built AI-driven platforms, and scaled teams from prototype to production.
The Track Record
Two decades of building, shipping, and occasionally breaking things across startups and scale-ups.
Years of Experience
Funding Raised by Portfolio Companies
Companies & Startups
What others say about working with me
I've had the pleasure of working together with Coen on a roller coaster startup venture in both Amsterdam and Silicon Valley. During this time, he has routinely impressed me with the ease with which he picks up new technologies, architected two production systems in two different frameworks, and overall by his sheer work capacity. In addition, as our CTO he has shown great technical leadership over our small team of developers, and in general I consider him one of the best technical minds that I know. I recommend him wholeheartedly.
PTPeter TegelaarFractional Chief AI Officer | ex-Klarna, ex-YC
Coen did great work at Wakoopa rewriting and improving our recommender system and version parser. He needs very little time to understand complex problems and solving these problems with the right tools, even if he needs to learn them from scratch. Coen is passionate about everything related to statistics and machine learning systems. Very easy to get along with and works well in a team.
WBWouter BroekhofTech Person
Over the past months I hired Coen as a Rails developer for a scrum based web project we ran for an educational publisher. Coen has proven to be a hard working consultant, a pure teamplayer with a positive attitude and a strong can-do mentality. This guy is highly recommendable!
BTBart ThijsProject & Programma Management
Frequently Asked Questions
Get in touch
Have a project in mind, or just want to talk shop? Drop me a message.
Send me a message
I typically reply within a few days.