# WebSocket > Real-time bidirectional communication with WebSocket support. ```html [index.html] CrossWS Test Page

{{ message.user }}

Avatar

{{ message.text }}

{{ message.date }}

` ``` ```ts [nitro.config.ts] import { defineConfig } from "nitro"; export default defineConfig({ serverDir: "./", renderer: { static: true }, features: { websocket: true }, }); ``` ```json [package.json] { "type": "module", "scripts": { "dev": "nitro dev", "build": "nitro build" }, "devDependencies": { "nitro": "latest" } } ``` ```json [tsconfig.json] { "extends": "nitro/tsconfig" } ``` ```ts [vite.config.ts] import { defineConfig } from "vite"; import { nitro } from "nitro/vite"; export default defineConfig({ plugins: [nitro()] }); ``` ```ts [routes/_ws.ts] import { defineWebSocketHandler } from "nitro"; export default defineWebSocketHandler({ open(peer) { peer.send({ user: "server", message: `Welcome ${peer}!` }); peer.publish("chat", { user: "server", message: `${peer} joined!` }); peer.subscribe("chat"); }, message(peer, message) { if (message.text().includes("ping")) { peer.send({ user: "server", message: "pong" }); } else { const msg = { user: peer.toString(), message: message.toString(), }; peer.send(msg); // echo peer.publish("chat", msg); } }, close(peer) { peer.publish("chat", { user: "server", message: `${peer} left!` }); }, }); ``` This example implements a simple chat room using WebSockets. Clients connect, send messages, and receive messages from other users in real-time. The server broadcasts messages to all connected clients using pub/sub channels. ## WebSocket Handler Create a WebSocket route using `defineWebSocketHandler`. ```ts [routes/_ws.ts] import { defineWebSocketHandler } from "nitro"; export default defineWebSocketHandler({ open(peer) { peer.send({ user: "server", message: `Welcome ${peer}!` }); peer.publish("chat", { user: "server", message: `${peer} joined!` }); peer.subscribe("chat"); }, message(peer, message) { if (message.text().includes("ping")) { peer.send({ user: "server", message: "pong" }); } else { const msg = { user: peer.toString(), message: message.toString(), }; peer.send(msg); // echo peer.publish("chat", msg); } }, close(peer) { peer.publish("chat", { user: "server", message: `${peer} left!` }); }, }); ``` Different hooks are exposed by `defineWebSocketHandler()` to integrate with different parts of the websocket lifecycle. ## Learn More - [Routing](/docs/routing) - [crossws Documentation](https://crossws.h3.dev/guide/hooks)