Build a game

Rare SDK

What @rare/sdk does, how a game reaches Rare on the device and off it, and where to start.

@rare/sdk lets a game sell, buy and claim Sui items without carrying a Sui SDK. It has two halves.

Half	Import	Runs in	What it does
Client	`@rare/sdk`	The game: a web page, or a native game with a JavaScript host	`me`, `inventory`, `sell`, `buy`, `claim`, `open`, `licence` and notices. Rare opens the sheets and does the chain work.
Server	`@rare/sdk/server`	Your game server (Node 22 or later)	Signs vouchers with your game key, verifies them, and reads ownership from the API.

The package is ESM and CommonJS, fully typed, tree-shakeable and has no dependencies in the client half. The server half needs @mysten/sui as a peer dependency.

Pre-release. @rare/sdk and create-rare-game are not on npm yet, and the item contract they claim against (rare_items) is not published. Everything on these pages is tested against a mock of the Rare Local API.

One set of calls, three transports

Rare.connect looks for the best way to reach Rare, in this order.

Transport	`rare.transport`	Where	How it talks
Launcher, web game	`launcher-web`	A web game running in Rare Launcher	The `rare:platform` feature of the injected Rare Wallet
Launcher, native game	`launcher-native`	A native or Proton game started by Rare Launcher	The Rare Local API on `127.0.0.1`, found through the `RARE_API`, `RARE_TOKEN` and `RARE_GAME` environment variables
Web	`web`	Anywhere else: a browser, a Steam or Epic build, a phone	rare.market in the system browser, plus the public API

The calls and their results are the same on all three. Two differences matter:

On the device sell, buy and claim open Rare's own sheet over your game and answer when the player is done.
On the web transport the sheet is a rare.market page. Those calls answer pending right after the page opens, and the real result arrives as a notice.

A game can never move anything by itself. Every action goes through the player's own review and PIN.

Where to go next

First game in a weekendFrom sign-up to a sponsored item claim, using npm create rare-game.SDK referenceEvery call, option, result and error code.Voucher signingThe exact bytes your game key signs, replay rules and key rotation.Check your gamenpx @rare/sdk check and running the game in Rare Launcher.