Free download

Turn Your Game Into Co-op

A free kit: a single-player browser game I wrote, the one prompt that turned it into 2-player online co-op in Claude Code, and the result with its small Node server. How host and guest share one game, how to play it with a friend on the same Wi-Fi or over the internet, a prompt template for your own game, and the honest catch: latency, cheating and hosting. Only for games you are allowed to change.

The download starts right away; the link also comes by email.

Without the newsletter box you get exactly one email with your link; the address is deleted after 7 days.

What is inside
  • solo/index.html Ember Run, the single-player game before the prompt: one HTML file, no libraries.
  • coop/ The co-op result: host and guest in one file, plus server.mjs, a WebSocket relay with 4-letter room codes.
  • PROMPTS.md The exact prompt I used, a template for your own game, a refactor prompt and four follow-ups (4 players, reconnect, hardening, deploy).
  • How it works Host-authoritative co-op in plain words: who runs the game, what is sent, why the screens stay in sync.
  • Play with a friend Two windows on one computer, the same Wi-Fi, or over the internet with a tunnel or your own server.
  • The honest catch Latency, cheating, hosting the relay, what to add before you put it online, and which games you may not change.

A browser for the solo game. Node.js 20 or newer for the co-op server. Claude Code (or another coding agent) to repeat the prompt on your own game. Your own game, or an open-source game whose licence allows changes. The kit is in English.

Fabian Faraz Farid · Imprint · Privacy