Your startup needs technical leadership — not just another developer.

I’m a fractional CTO who makes the technology decisions so you can focus on growing your business. No jargon, no guesswork — just a clear technical direction.

Book a conversation

Who I work with

Non-technical founders building a tech product

You have the vision and the customers, but you need someone who can translate that into the right technology choices — and make sure they get built properly.
Startups scaling past their MVP

Your agency-built prototype is breaking under real usage. You need someone to assess what you have, decide what to keep, and chart a path to a system that scales.
Funded startups hiring their first engineers

You’re ready to build a team but don’t know how to evaluate developers or set technical direction. I help you hire right and get your engineering culture started.

Start with a Technical Review

A one-day assessment of where your technology stands and what to do next. You get a written report covering:

How your current setup is working (and where it’s not)
The biggest risks that could slow you down or cost you money
What to prioritize in the next 3 months
Clear recommendations you can act on immediately

€1,000. Fixed scope. No ongoing commitment required.

Most reviews uncover quick wins that save far more than the cost — and give you clarity on whether you need ongoing technical leadership.

Book a review

Selected work

Helped a reinsurance technology startup build and ship their core platform — taking the product from early architecture to handling live deals in production. Read about solving a production issue →

Served as technical lead for a construction IoT startup, making architecture decisions that let them scale from pilot to production. Improved device performance 7x along the way. Read the full story → · The 7x improvement →

Mentored early-stage founders on technical strategy through accelerator programs, helping non-technical teams make confident technology decisions without overspending.

How we work together

Advisory retainer

A few hours per week of strategic guidance. I review your technical decisions, help you evaluate hires and vendors, and make sure you’re spending your budget wisely.

Operational retainer

Embedded in your team 1–2 days per week. I set the technical direction, work alongside your developers, and make sure things get built right.

Project engagement

Fixed-scope builds. I design and deliver the system end to end. You get a working product, not a specification document.

All engagements start with a conversation about your situation. I'll tell you honestly whether I can help.

About

I'm Jappie Klooster. I’ve spent years helping startups make the right technical decisions — and then building the systems to back them up. Not advice that sits in a document — decisions and delivery.

I use technologies chosen for reliability and long-term maintainability (including Haskell and Nix), but the technology is an implementation detail — what matters is that your product works, scales, and doesn’t fall over when your users show up.

For more writing and case studies, visit my blog.

Let's talk about your startup

If you’re building something and need technical leadership you can trust, get in touch. I’m always happy to have an initial conversation — no commitment required.