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Probably one of the hardest lessons I had to learn

If you spend enough time in US business or finance conversations, one word keeps showing up: equity . Coming from a German-speaking, central European background, I found it surprisingly hard to fully internalize what that word means. More t…

Whenever a new technology shows up, the conversation quickly splits into camps. There are the people who reject it outright, and there are the people who seem to adopt it with religious enthusiasm. For more than a year now, no topic has bee…

Today I’m very happy to share that Mario Zechner is joining Earendil . First things first: I think you should read Mario’s post . This is his news more than it is ours, and he tells his side of it better than I could. What I want to do here…

I've sold out

About five months ago I wrote about Absurd , a durable execution system we built for our own use at Earendil, sitting entirely on top of Postgres and Postgres alone. The pitch was simple: you don’t need a separate service , a compiler plugi…

Thoughts on slowing the fuck down

Trees take quite a while to grow. If someone 50 years ago planted a row of oaks or a chestnut tree on your plot of land, you have something that no amount of money or effort can replicate. The only way is to wait. Tree-lined roads, old gard…

Because code gets cheaper and cheaper to write, this includes re-implementations. I mentioned recently that I had an AI port one of my libraries to another language and it ended up choosing a different design for that implementation. In man…

How I use Pi to distill multiple context windows into exactly what I need

Historically, writing code was slower than reviewing code. It might not have felt that way, because code reviews sat in queues until someone got around to picking it up. But if you compare the actual acts themselves, creation was usually th…

Last year I first started thinking about what the future of programming languages might look like now that agentic engineering is a growing thing. Initially I felt that the enormous corpus of pre-existing code would cement existing language…

If you haven’t been living under a rock, you will have noticed this week that a project of my friend Peter went viral on the internet . It went by many names. The most recent one is OpenClaw but in the news you might have encountered it as…

Regular readers of this blog will know that I started a new company. We have put out just a tiny bit of information today , and some keen folks have discovered and reached out by email with many thoughtful responses. It has been delightful.…

Don't let AI make you the boss no one respects anymore

A look back at 2025

Lessons I learned while building my own coding agent from scratch.

An email I wrote over 2 years ago

A rambling rebuttal to Armin's claim that LLM APIs are a state synchronization problem.

Got Bash and some code interpreter? Skip MCP.

How I turned imposter syndrome into my learning superpower

It's not about working more - it's about caring more

Building a JavaScript AST interpreter in JavaScript: scope isolation, ES5 implementation, and all the footguns along the way.

are the best tool to shape the culture you want

... is what stands between you and what you want

A data-driven comparison of MCP and CLI approaches for coding agent terminal control

Why I share what I actually think and feel

cc-antidebug patches Claude Code to enable Node.js debugger support for SDK-based apps and restores the /cost command functionality for Max plan users

Exploring how to track and analyze changes in Claude Code's system prompts and tools to understand AI assistant evolution

Reflections on how I transitioned from Engineer to Director of Engineering at Sentry

Some tips to land the best job you ever had

A story how I ended up at Sentry

Treating LLMs as shitty general purpose computers we program with natural language. Because throwing shit at the wall wasn't working anymore.

How I built a simple portable audio player for my boy, summoning the spirit of the Gameboy

How to programmatically turn on LEDs and read button states

Exploring the absolute basics.

The story of a programmer trying to electronics

Fun little vacation project for fun and zero profit.

Reminiscing about the times I didn't watch TV at night but built stuff.

Thoughts on acquiring computational thinking skills based on my own experience.