Shipping real systems, not demos.
Agent architectures, retrieval that actually grounds, prompts that survive contact with users. I write about what breaks in production — not what looks good in a thread.
Swiss engineer and founder writing about AI, growth, and what it actually takes to ship startups that work. No frameworks-as-religion, no LinkedIn posturing — just field notes from the build.
I'm Jonas. I studied CS at DTU in Copenhagen, then moved back to Switzerland. In 2022, my brother — a construction contractor — couldn't find a single excavator operator in Germany. The market was empty. So I built Crafthunt: a recruiting platform for the trades. We found two operators in Poland with €47 in ads. That problem led directly to BauGPT — an AI platform now used by 70K+ workers and 1,000+ construction companies.
Today I split my time between product, growth, and figuring out how AI actually gets adopted in a 150-year-old industry. Enterprise clients like STRABAG, BAUER, and Max Bögl use BauGPT in production. We got there without a traditional sales team — scrappy acquisition loops, SEO that compounds, onboarding you can complete in 90 minutes. That's the playbook I write about here: the AI Growth Engineer approach.
This blog is where I write it all down. Some posts are essays I've chewed on for weeks. Some are field notes from a bug I just shipped a fix for at 2 a.m. I try not to publish anything I haven't personally tested, and I'll tell you when something didn't work for me — because those are usually the posts I wish I'd read a year earlier.
If you're building with AI, growing something scrappy, or trying to figure out whether a startup idea is real — you're probably in the right place. Subscribe below and I'll send one note a week. No fluff, just what works (and what didn't).
Agent architectures, retrieval that actually grounds, prompts that survive contact with users. I write about what breaks in production — not what looks good in a thread.
Scrappy acquisition loops, SEO / GEO that compounds, onboarding that converts. I test things on my own products first, then tell you whether they worked.
Founding BauGPT taught me which "best practices" are religion and which actually save you. Expect field notes from the middle of the build, mistakes included.
AI engineering, growth hacks, and messy lessons from shipping BauGPT. Unsubscribe anytime. I'll even miss you.