***

id: 7d7d2884-9319-4c8e-9329-37e8dcabcd89
title: PubSub Client
sidebar-title: Client
slug: /node/reference/pubsub/client
description: PubSub Client reference for publishing and subscribing to messages.
position: 1
max-toc-depth: 3
----------------

[events]: /docs/server-sdk/v3/node/reference/pubsub/client/events

The PubSub Client enables real-time publish/subscribe messaging. It connects to SignalWire and allows you to subscribe to channels and publish messages to them.

```javascript
import { PubSub } from "@signalwire/realtime-api";

const pubSubClient = new PubSub.Client({
  project: "<project-id>",
  token: "<api-token>",
});
```

After instantiating, call `subscribe()` to join channels, then use `publish()` to send messages and listen for the `message` event to receive them. See [Events][events] for all available events.

## Constructor

▸ **new PubSub.Client**(`opts`): `PubSub.Client`

Creates a new PubSub Client instance.

#### Parameters

| Name                       | Type      | Description                                            |
| :------------------------- | :-------- | :----------------------------------------------------- |
| `opts.project`             | `string`  | **Required.** SignalWire project ID.                   |
| `opts.token`               | `string`  | **Required.** SignalWire API token.                    |
| `opts.debug.logWsTraffic?` | `boolean` | Log WebSocket traffic for debugging. Default: `false`. |

## Examples

### Subscribing to channels

```javascript
await pubSubClient.subscribe(["notifications"]);

pubSubClient.on("message", (message) => {
  console.log("Received:", message.content);
});
```

### Publishing messages

```javascript
await pubSubClient.publish({
  channel: "notifications",
  content: { type: "alert", text: "New update available" },
});
```