Still in school. Already shipping.
I am Marcus, nineteen, a student at Rosborg Gymnasium in Vejle and a self-taught developer. I make things for people I can actually see using them: classmates opening Lectio, a restaurant filling its shifts, a jailbreak server full of players.
I started by rebuilding things I used and thought could be better. That habit turned into a Chrome extension, a scheduling system, a set of game-server plugins and a few iOS tools, and most of them are still running.
Tarnix
My company. I build internal software for Danish businesses and hand it over.
Tarnix builds shift planning, customer records and internal tools for small Danish companies. One payment, the customer owns the system and the accounts afterwards, and there is no subscription running in the background. The first system is the one running at Restaurant Børkop Vandmølle.
tarnix.dkHow I work
The constraint is the interesting part.
No developer account meant no native app blocker, so BRICK is built out of Shortcuts and an NFC card. Static hosting only meant the trust in Vagtflow had to live in the database.
Nobody should need the manual.
A schedule should tell you where you are in the day without you reading anything. That is why LectioLux has a time-rail and a live line instead of a grid of boxes.
Ship it to real people, then keep it running.
Every project on this site has users who would notice if it broke. That changes how carefully you handle a migration, a permission, a default.
What I build with
Grouped by where I use them. The bigger the name, the more days a week it shows up.
Languages
- JavaScript daily
- CSS daily
- TypeScript comfortable
- C# comfortable
- Swift comfortable
- Python comfortable
- SQL comfortable
Web
- Chrome extension APIs daily
- Supabase comfortable
- PostgreSQL and RLS comfortable
- WebRTC comfortable
- PWA comfortable
- Netlify comfortable
- Astro learning
Apps and servers
- iOS Shortcuts daily
- CounterStrikeSharp comfortable
- MySQL comfortable
- SwiftUI comfortable
- FastAPI comfortable
- SwiftData learning
- GameKit learning
Hardware and making
- 3D printing comfortable
- Electronics comfortable
- Raspberry Pi comfortable
- NFC comfortable
- Fusion 360 learning
- NetLogo learning
Beyond the screen
I 3D-print parts when a project needs a case or a mount, and I can get by in Fusion 360 when nothing ready-made fits. I build small electronics and Flipper-style hardware, and run NetLogo simulations when a problem is more about behaviour than code. A Raspberry Pi at home runs a FastAPI service that controls the lights through Philips Hue, behind a Cloudflare tunnel.
Right now
- Finishing LectioLux 3.0, the edition that redraws Lectio from scratch.
- Testing an iOS card game with Texas Hold'em and Blackjack engines on real devices.
- Planning a Screen Time blocker for short-form video.
Education
- 20242027 Rosborg Gymnasium og HF Upper secondary (STX), mathematics
- 20232024 Vivild Gymnastik- og Idrætsefterskole 10th grade at a sports boarding school
- 20132023 Englystskolen Primary and lower secondary, grades 0 to 9
Working on something?
Email reaches me directly, and I reply.