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Documentation Index

Fetch the complete documentation index at: https://openturn.io/docs/llms.txt

Use this file to discover all available pages before exploring further.

Before you deploy to openturn cloud, you want to prove the multiplayer flow on your own machine. openturn dev runs a production-shaped hosted stack against your project’s app/ folder. No cloud credentials, no network configuration.

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Prerequisites

You need a project with the three-file layout:
  • app/game.ts exporting game and match.
  • app/page.tsx rendering the React UI.
  • app/openturn.ts with metadata. For hosted, set runtime: "multiplayer".
See tutorial: tic-tac-toe multiplayer for the layout.

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Start the server

From the project root: 
openturn dev app
Or with options: 
openturn dev app --port 4010 --db .openturn/dev.sqlite
The CLI starts a Bun HTTP server that:
  • Serves the bundled React app at /play/<deploymentID>.
  • Hosts a WebSocket endpoint for @openturn/client to connect to.
  • Runs your authored game inside @openturn/server’s createRoomRuntime.
  • Persists rooms in a SQLite database (default .openturn/local-dev.sqlite).
  • Signs anonymous session tokens with @better-auth so each window gets its own user.

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Play

Open the play URL in two browser windows. In the first window, create a room. Share the invite URL (the CLI also prints it on room creation) to the second window. Both windows land in the same lobby. When the lobby reaches its minimum player count, LobbyRuntime signs game tokens and the clients transition into the hosted match. Moves dispatched in either window go over WebSocket to the shared runtime and broadcast back as BatchApplied messages.

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Inspect what is happening

The CLI logs every room action, token issuance, and WebSocket event. Open the SQLite database with any SQLite client to see the persisted room records:
  • openturn_rooms — current room state (checkpoint, log, match).
  • openturn_room_players — seat assignments.
  • openturn_audit_events — room audit log.
Because rooms are persisted, you can stop the server and resume; clients reconnecting pick up from the last revision.

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Hot reload

openturn dev watches app/game.ts. Saving a change rebuilds the bundle and swaps the deployment in-process. Open rooms keep running against the previous deployment version; new rooms pick up the update. For serious game-logic iterations, reset by deleting the SQLite file between runs or passing a fresh --db path.

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Resetting a dev database

rm .openturn/local-dev.sqlite
openturn dev app
A new schema is created on boot.

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Using the runtime programmatically

If you need a custom dev shell, the CLI server is also exported: 
import { startLocalDevServer } from "@openturn/cli";
import { loadGameDeployment } from "@openturn/server";

const deployment = loadGameDeployment(await import("./my-deployment.ts"));
const server = await startLocalDevServer({ deployment, port: 4010 });
You will rarely need this; openturn dev covers the common case.