I'm Mikołaj, a backend developer from Katowice, Poland, working in Node.js and TypeScript.
Most of what I build starts as a problem of my own. I write the tool, then run it myself on a Raspberry Pi 5 at home, behind my own reverse proxy. The one thing here built for someone else is the booking system of my family's climbing school, in production since April 2026.
I started as a kid with Scratch, Minecraft redstone and an after-school web class, then spent a few years producing music. I came back to programming in September 2025 to build a store for my own beats, and have been building since.
Stack: Node.js, TypeScript, Express, Fastify, React, SQLite, Docker, GitHub Actions, nginx, Linux.
Every repository has CI on every push and a README that says how to run it.
- climbing-booking: class sign-up for my family's climbing school. 670 registered accounts and 750+ bookings so far. Waiting list with automatic promotion, passwordless login, instructor and admin panels. Express, SQLite, 174 tests.
- mindgate: I wanted to use the models on my desktop PC from anywhere. It became one OpenAI-compatible API in front of that PC, which it wakes with Wake-on-LAN and lets sleep when idle, and the cloud models I use. Per-app keys, budgets and a local-only flag. Fastify, SQLite, 500+ tests.
- everything-app: the AI workspace I wanted and could not buy. Any model through one API, a code agent in a Docker sandbox per project, a browser it drives, Git through a proxy that keeps credentials out of the sandbox, and an approval gate on every shell command. Early; 1,000+ tests across six packages.
- OBSIDIAN-LIVESYNC: my Obsidian vault is where I plan everything, so AI agents read and edit it through MCP and it stays in sync with Google Calendar and Tasks. Paths are checked against traversal and symlinks; nothing is ever permanently deleted. In daily use.
- nginx-reverse-proxy: the nginx in front of all of the above since September 2025. HTTPS, per-client rate limits, each app on its own Docker network with no published ports.