# Messages, events and raised hands

Send chat, transient events and persistent participant metadata.

## Imports

```tsx
import { useEffect } from 'react'
import { useLocalParticipant, useMessages, useParticipants, useRoom } from '@relayrtc/react'
```

## Text messages

Your token needs `messages:send`.

```tsx
const { messages, send, clear } = useMessages()
await send('Hello everyone')
```

Messages are limited to 4,000 characters. Whitespace-only text is rejected. The React provider keeps 100 messages by default; `messageHistoryLimit` changes that local limit.

`clear()` clears your local history. It does not delete messages for other participants. Chat history is not durable across a reload.

## Custom events

Use custom events for transient actions that should reach current participants.

Sending custom events also requires messages:send.

```tsx
const { room } = useRoom()

useEffect(() => {
  if (!room) return
  return room.events.subscribe((event) => {
    if (event.name === 'reaction.sent') console.log(event.data)
  })
}, [room])

await room?.events.emit('reaction.sent', { emoji: 'hello' })
```

Names start with a lowercase letter and contain up to 64 lowercase letters, digits, underscores, dots or hyphens. Payloads must be JSON values. Events are not durable messages.

## Raised hands

Use participant metadata when the state should appear in presence snapshots.

Updating metadata requires metadata:update.

```tsx
const local = useLocalParticipant()

await local?.updateMetadata({
  ...local.metadata,
  handRaised: true,
})
```

```tsx
const participants = useParticipants()
return participants.map((person) => (
  <p key={person.id}>{person.name}{person.metadata.handRaised === true ? ' · Hand raised' : ''}</p>
))
```

Metadata updates replace the participant metadata object. Spread existing values when keeping other fields. A raised-hand button is an application feature built on metadata, not a separate SDK method.