Spectrum Online

When I was 7 or 8, my brother and I had a ZX Spectrum 48K. I learned to program BASIC on it through trial and error, and that became the foundation for my work years later. I was very good at Match Day, and I always wished I could play against more people.

One day I thought: how cool would it have been to play Match Day online? And why not try building it? Once the online play system was in place, I decided to add more games. That’s how Spectrum Online was born: the original games, in the browser, against a friend in their own home.

All the code was written with Claude, Anthropic’s AI. I didn’t write a single line: I kept telling it what I wanted and Claude programmed it. As a kid I learned on the Spectrum through trial and error; the process now is similar, but my part is knowing what to ask for.

For now there are four: Match Day and Match Day II (Ocean), Match Point (Psion / Sinclair) and Fernando Martín Basket Master (Dinamic). The catalogue will keep growing, and users can suggest games.

Spectrum games were made for two players sitting at the same keyboard. The challenge is letting two people play from different homes without touching the original game and without running a game server of my own.

The solution: the emulator only runs in the browser of whoever creates the match. The game image is sent to the guest as video over WebRTC, and their keystrokes travel back over a data channel (PeerJS) and are translated into player 2's keys. The guest joins with a 5-letter code, watches the match live and plays with their own keyboard.

Then there are the details of each game. Match Day ships with player 1 set up for a joystick the emulator doesn't have. Claude found where in the Spectrum's memory the game stores its controls, and the site rewrites them on load.