# MessageMetadata

> **Interface** in `@langchain/react`

📖 [View in docs](https://reference.langchain.com/javascript/langchain-react/MessageMetadata)

Metadata tracked per message id. Surfaced to applications via
`useMessageMetadata(stream, messageId)`.

## Signature

```javascript
interface MessageMetadata
```

## Properties

- `optimisticStatus`
- `parentCheckpointId`

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[View source on GitHub](https://github.com/langchain-ai/langgraphjs/blob/9ae75600dd84d6b2bc736e33baaf66a556d61c49/libs/sdk/src/stream/message-metadata-tracker.ts#L23)