To send a message to a topic, use `publish()` method with your topic name and the message:
```javascript
await PubSub.publish('myTopic1', { msg: 'Hello to all subscribers!' });
```

If multiple providers are defined in your app you can pass the message to a specific provider:
```javascript
await PubSub.publish('myTopic1', { msg: 'Hello to all subscribers!' }, { provider: 'AWSIoTProvider' });
```

You can also publish a message to multiple topics:
```javascript
await PubSub.publish(['myTopic1','myTopic2'], { msg: 'Hello to all subscribers!' });
```

<Callout>

**Note:** If you do not include a specific provider it will publish a message to all of the configured PubSub providers in your app.

</Callout>