Senior full-stack engineer from Munich. Building for the web since 2008, with Ruby on Rails since 2011, from features down to the infrastructure that runs them. Worker-owner at the Tech-Genossen eG, a tech cooperative.
Most of my work is closed source. From 2017 to 2024 I worked on webgate.io, a video review platform for film and TV: Rails and Vue.js features, a new transcoding infrastructure, a GlusterFS storage cluster, and a better delivery process with feature staging, CI, code-quality tooling and regular retrospectives. Before that gutefrage.net, where I mentored an apprentice and organised coding dojos and IT drinkups, CHECK24 and YiGG. With the Tech-Genossen I relaunched oekotest.de on Rails, built lunch-o-mat.com and a ton of smaller projects.
I like small teams, being close to the product and the people who use it, and boring, well-tested software with few dependencies. In my spare time I build small self-hosted tools for our household – and publish most of them.
🏠 Home & energy
- ZiWoAS – energy dashboard for our flat: balcony solar, Shelly and Fritz!DECT plugs via MQTT, Govee lights over LAN. Rails, moving to Elixir/Phoenix.
- ziwoas-airquality – Sensirion SEN66 on an RP2040, Rust bridge to MQTT.
- hedgehog-fit – TRMNL e-ink plugin: an 80s-fitness hedgehog nudges you into a one-minute exercise.
💶 Money
- Zipfelkasse – shared expenses for one household, inspired by Spliit. Crystal + SQLite, one binary, YNAB sync, and an MCP server so an AI can answer "what did we spend on groceries?".
🌐 Web
- felt-css · docs – Bootstrap class names, two looks: clean, or every card cut from wool felt.
- Feather-Page CMS – manage small static websites that look hand-coded and load nothing external. Rails, moving to Phoenix.
🤖 AI tooling
- pi-container-vm – runs every tool of the pi
coding agent inside a hardened Apple
containerVM; only the project directory is mounted.
My side projects are also my mad-scientist lab 🧑🔬 I'm fairly language-agnostic and like trying new ones –
hence Crystal, Rust and the Phoenix ports – and I experiment with how long a leash I can give coding agents.
I hold these projects to looser standards than client work; that's where the claude/… branches and the
occasional huge pull request come from.
Ten smaller projects, 2011–2021
| Year | Project | What it does |
|---|---|---|
| 2021 | zunzuncito | Featherlight CMS for static websites, the predecessor of Feather-Page |
| 2021 | zaunkoenig | Lightweight Jekyll theme |
| 2015 | lunch-o-mat | Blind-date lunches between colleagues; grew into lunch-o-mat.com at the Tech-Genossen |
| 2013 | dotfiles | My shell setup, 25 ⭐ |
| 2013 | gitshots | Takes a webcam picture of me on every commit |
| 2013 | cask-probe | Checks whether Homebrew casks still install |
| 2012 | Cruise-Pricesnapper | Samples cruise prices to find the best moment to book |
| 2011 | Ethan | XMPP bot for Scrum teams, Node + CoffeeScript |
| 2011 | Florette | A small language that compiles to PHP |
| 2011 | ZWeather | Web frontend for our weather station |
Contributions: 32 merged pull requests to Homebrew Cask in its early days (2013) · fixes for redirector and castic · organised the OpenHack nights in Munich (2013)
Ruby on Rails · Hotwire · Elixir/Phoenix LiveView · PostgreSQL · SQLite · Crystal · Go · Rust · Docker · Ansible
- 🌍 rocu.de – my site since 2001
- 🎼 The username is a nod to Dmitri Shostakovich.
Most of these repos are built for our household, so I keep their scope tight and don't take pull requests. Issues and forks are very welcome.