# chain.wtf SDK

Build games for chain.wtf, from solo wagers against the house to multiplayer battles for a shared pot. Pick an SDK, spin up a simulator, and start dealing.

:::note[Current SDK checkout]
- <span id="chainwtf-sdk-docs" data-chain-sdk-checkout></span>`@chain-protocol/casino-sdk@0.7.0`
- `@chain-protocol/pvp-sdk@0.7.0`

This guidance reflects this checkout and may include unreleased changes.

[Casino changelog](/sdk/casino/changelog/) [PvP changelog](/sdk/pvp/changelog/)
:::

Docs for building iframe games compatible with Chain protocol and that run inside the Chain.wtf host application.

## SDKs

- [Casino SDK](/sdk/casino/) — single-player games where the player wagers against house liquidity.
- [PvP SDK](/sdk/pvp/) — multiplayer games where players wager against each other into a
  shared pot.

## Start a game

For a casino game, prefer the [Slot Engine](/sdk/casino/slot-engine/) or the
[Graph Engine](/sdk/casino/graph-engine/) to a contract of your own. An engine game needs no Solidity,
only its frontend is reviewed, and it joins the offering as soon as it deploys.

Create a game from an example with the `chain` command, then play it in the SDK simulator:

```sh
npx @chain-protocol/cli init casino my-game
npx @chain-protocol/cli init pvp my-game
```

With Bun, use `bunx` instead of `npx`. [Getting Started](/sdk/casino/getting-started/) walks through a
casino game from an empty directory to a played round, and the
[PvP Local Simulator](/sdk/pvp/local-simulator/) page does the same for a PvP game.

To add an SDK to an existing project, install it with the CLI at the same version:

```sh
npm install @chain-protocol/casino-sdk   # or @chain-protocol/pvp-sdk
npm install --save-dev @chain-protocol/cli
```

With Bun, run `bun add @chain-protocol/casino-sdk` and `bun add --dev @chain-protocol/cli`.

## Package entry points

- Casino: `@chain-protocol/casino-sdk`, `@chain-protocol/casino-sdk/guest`,
  `@chain-protocol/casino-sdk/contracts/*`, `@chain-protocol/casino-sdk/slot-engine` and
  `@chain-protocol/casino-sdk/graph-engine`.
- PvP: `@chain-protocol/pvp-sdk`, `@chain-protocol/pvp-sdk/guest`,
  `@chain-protocol/pvp-sdk/liveness`, `@chain-protocol/pvp-sdk/spectator` and
  `@chain-protocol/pvp-sdk/contracts/*`.

`./host`, `./simulator` and `./conformance` are internal to both SDKs. They serve the Chain.wtf
host, `chain dev` and `game-verify`, sit outside semver and can change in any release.