msimcity
A web-based, multiplayer, unbounded city builder platform. three.js on the client,
an authoritative TypeScript simulation server over WebSockets, and a shared
package so both sides agree on the world format.
The core idea: players buy and manage land parcels, but citizens are not
theirs. A citizen lives in whichever residential building spawned them, looks
for the nearest job anywhere on the connected road network, commutes there every
day, pays income tax to whoever owns the parcel they work in and property tax to
whoever owns the parcel they live in. Players compete and cooperate through
zoning, roads and tax rates, not through walls.
Run it
npm install
npm run dev # server on :8080 and Vite client on :5173, both bound to 0.0.0.0
Opening the game
Open http://<your-lan-ip>:5173/ (the Vite banner lists the addresses). The page is a home page with three ways in (docs/demo.md, "The home page"):
- Explore a city: a card for every demo the server lists (London, the showcase, the focused demos), live status while one is built; Open goes to
?demo=<id>, read-only on a public showcase.
- Play: your own city in this browser, no server and no account: Continue, New game from zero or Sandbox. The game server serves the offline build at
/play/, saves live in this browser (docs/local-mode.md).
- Multiplayer: the public servers in
packages/server/servers.json (ours is listed as closed until sign-in exists), and on a dev or UAT server "This server's live world" with the mayor-name join form, folded.
Above these sits a showreel strip: ten building thumbnails, three short clips of the Showcase and three lines on how it plays, all pre-rendered (so the page has no WebGL) by node packages/client/scripts/showreel.mjs into packages/client/src/showreel/ (docs/demo.md, "Showreel").
Every browser that joins a live world shares it. A link with any query (?demo=london, ?name=Ana, ?ws=host:port, ?local, ?at=x,y) skips the home page and opens the game as before; /?go is the game's bare page (the join form, or DEFAULT_DEMO).
Buildings are data: packages/shared/src/buildings/ holds one file per kind family, and
npm run buildings:compile (run automatically by dev and build) turns it into the tables the
game reads. /viewer.html shows every kind, level and design on a turntable by day and night.
Format and a worked example: docs/buildings.md. npm run buildings:check is its snapshot test.
Landmarks (a famous building, a town hall, a monument): docs/landmarks.md is a brief a person or a model can follow on its own, with a template, a worked example and a draft path (landmark-drafts.ts, viewer tag draft); npm run landmarks:check checks them.
Production: npm run build (add npm run build:local for /play/) then npm start. The server then serves the built
client, the offline build under /play/ and the WebSocket on one port (default 8080). A Dockerfile is included;
mount /data to keep the world across restarts.
This is the beginning of the README. Read the rest at the original. Read the full README ↗
