Build your game on GrowBlocks.

Start in five minutes

You need Node.js 18 or later. Then:

npx growblocks new my-game     # the starter kit, always the latest
cd my-game
npx growblocks dev             # play it at http://localhost:5173/play.html

With Claude Code (recommended): run claude in that folder and describe your game. The folder's .mcp.json gives Claude the GrowBlocks tools, so it can read the API, check the game with a screenshot, add blocks, push a test build and read your review status by itself. Try:

Make a multiplayer [your idea] game on GrowBlocks. Check it with a screenshot and fix anything that's off, then push a test build and give me the link.

Writing it yourself: edit game.js and reload play.html. Here is a whole game:

export default async function game(gb){
  gb.world.style('sunset');
  gb.world.ground({size:60});
  gb.world.box({size:[1,1,1],position:[0,4,-4],color:'#ff5fa2',physics:'dynamic'});
  const me=gb.player.spawn({position:[0,1,6]});
  const room=(await gb.net.join()).showPlayers();
  gb.onUpdate(dt=>{ if(gb.input.pressed('KeyM')) gb.chain.market(); });
}

play.html loads the GrowBlocks engine and runs your game.js, with real multiplayer rooms. Local builds simulate the chain, so you can build your mint and market flows before GrowBlocks reviews your game. Ship it from the terminal:

npx growblocks login                              # once: confirm a code in your browser
npx growblocks create my-game --name "My Game"     # once: your game's address and name
npx growblocks push                               # check + upload a test build, prints its link
npx growblocks submit                             # send it to GrowBlocks for review

The CLI manages your games and builds only: collections, your coin and earnings stay here in your browser. npx growblocks help lists every command; the guide explains them.

Build it with AI

The kit is made to be written by an AI assistant. Every game folder carries what an assistant needs to get it right first time: instructions it reads by itself (AGENTS.md, CLAUDE.md), the complete API (llms.txt, gb.d.ts), a checker that plays the game headless and hands back every error and a screenshot, and the GrowBlocks MCP server (.mcp.json).

Claude Code and Cursor pick up the MCP server by themselves: growblocks_docs, growblocks_check (with the screenshot), growblocks_blocks and growblocks_add_block, growblocks_push, growblocks_status, growblocks_submit. Elsewhere: claude mcp add growblocks -- npx -y growblocks mcp.

With a chat assistant (no file access): paste this, add your idea, and save its answer as game.js in your game folder.

Read https://growblocks.xyz/devkit/llms.txt carefully: it is the complete API of the GrowBlocks Dev Kit, and you may only use what it documents. Then write game.js for this GrowBlocks game:

[describe your game: the goal, the controls, what happens, single player or multiplayer]

Return the whole game.js in one code block. It must `export default async function game(gb){...}`, use gb.onUpdate for per-frame logic, never create a renderer or loop, never use localStorage, and work on phones (gb.input.move / gb.input.action).

No Node.js? Download the same starter kit as a zip, serve the folder with any web server that allows CORS, and upload it below.

Your games

Sign in to upload a game.

By downloading the starter kit or uploading a build you agree to the Dev Kit terms: your game is yours, the GrowBlocks engine is licensed only for games on GrowBlocks.

Review queue (GrowBlocks)