# Enable compression for WebSocket messages (/docs/guides/websocket/compression)

<!-- agent-signals: reading_time_min: 1 · est_tokens: 152 · updated: 2026-07-28 -->
Related: [Build a simple WebSocket server](/docs/guides/websocket/simple.md), [Build a publish-subscribe WebSocket server](/docs/guides/websocket/pubsub.md), [Set per-socket contextual data on a WebSocket](/docs/guides/websocket/context.md), [Add a dependency](/docs/guides/install/add.md)

Set the `perMessageDeflate` parameter to compress all messages with the [permessage-deflate](https://tools.ietf.org/html/rfc7692) WebSocket extension.

```ts server.ts icon="/icons/typescript.svg"
Bun.serve({
  // ...
  websocket: {
    // enable compression
    perMessageDeflate: true,
  },
});
```

***

To enable compression for individual messages, pass `true` as the second parameter to `ws.send()`.

```ts server.ts icon="/icons/typescript.svg"
Bun.serve({
  // ...
  websocket: {
    async message(ws, message) {
      // send a compressed message
      ws.send(message, true);
    },
  },
});
```