Idle game multiplayer browser game template for Net Forge, the open-source multiplayer browser game engine built for AI coding agents.

This is a template for an idle game that runs in the browser: BRINEWORKS, a complete multiplayer game you can start in one command and change in one file. A shared idle and incremental game: pumps draw brine, pans boil it into salt, kilns cut salt into crystals, and salt buys and levels more plants.

What you get

• Up to 8 players, each running a production chain on one shared salt flat.
• Five plant kinds to buy and level, and one contract the whole room fills together.
• Fixed-length shifts of fifteen minutes, then a fresh one starts.
• An authoritative room at 30 Hz; the economy is integer state on the server, so no client can mint its own output.
• Authoritative multiplayer. A room host owns the game state; every browser tab is a player. Locally, npm run play runs that host on your computer.
• Shared client/server simulation. The same ECS and Rapier physics code steps the world on the server and predicts your own player in the browser, with delta snapshots.
• three.js renderer with WebGPU, and a WebGL2 fallback.
• Bots and a headless playtest. npm run test plays the game with bots and reports what happened.
• TypeScript, MIT licensed. The library models, sprites and sounds the game uses are CC0.
• Ready for coding agents. AGENTS.md, CLAUDE.md, Cursor rules, Copilot instructions and the Net Forge MCP server in .mcp.json, .cursor/mcp.json and .vscode/mcp.json.

Measured with npm run test (2 bots, 1 minute of game time, Node 22, Apple M2 Pro):

Playtest report	Value
Ticks simulated at 30 Hz	1,800
Server cost per tick (mean)	under 0.005 ms
Softlock	none

The playtest also checks the economy: first payout after 199 s, at most 552 coins an hour a seat.

Every number above is play money and a local run. Longer runs: npm run test -- --minutes 4 --bots 4.

Start in one command

npx create-netforge my-game --template idle --yes
cd my-game
npm run play

Or press Use this template on GitHub, clone your new repository, and run:

npm install && npm run play

npm run play builds the game, starts a local room and opens http://127.0.0.1:4663. Open the same link in another tab for a second player. Space rakes salt by hand (or click your plot), keys 1 to 5 buy a plant, and S ships crystals.

You need Node.js 20 or newer. Use npm run play -- --no-open to print the link instead, --port 4700 if the port is taken, and --host 0.0.0.0 to let phones on your network join. Local play uses play money: no wallet, no chain and no hosted servers.

Change the rules

The whole game is src/game.ts: declarations against the typed API in @netforge/engine (the only import it may make). The template package @netforge/template-idle provides the renderer, netcode, physics, controls, HUD and bots.

npm run test        # compile src/game.ts and play it with bots; fails on a broken rule or a softlock
npm run typecheck   # the TypeScript check of src/game.ts
npm run play        # play the change (stop and start it again after each edit)

The template guide walks through the usual changes:

• Tune progress
• Change the shift and the contract
• Add an earn rule
• Check it with bots

llms.txt holds the rules the build enforces and recipes for common changes. Or ask your coding agent in plain words; AGENTS.md tells it where the rules live and how to test them.

Links

• Template guide: https://forge.netnet.capital/docs/templates/idle-game
• Net Forge engine: https://github.com/netnetdev/net-forge
• Docs: https://forge.netnet.capital/docs
• npm: create-netforge, @netforge/template-idle, @netforge/engine

Pinned to Net Forge 0.2.0. Not affiliated with other projects named NetForge. Local play runs the game's own code on your computer with your permissions; play only games whose code you trust.

License

MIT (LICENSE). The library assets are CC0 1.0.