> ## Documentation Index
> Fetch the complete documentation index at: https://novita.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Sandbox Metadata

Sandbox metadata lets you attach custom key-value information to a sandbox.

Common uses include:

* Connecting a sandbox to a user session.
* Saving custom user-related data for a sandbox, such as API keys.
* Linking a sandbox to a user ID so it can be reconnected later.

Metadata is provided when the sandbox is created. Later, it can be read when listing active sandboxes with `Sandbox.list()`.

<CodeGroup>
  ```js JavaScript & TypeScript icon="js" theme={"system"}
  import { Sandbox } from 'novita-sandbox'

  // Start a sandbox and attach custom metadata.
  const sbx = await Sandbox.create({
    metadata: {
      userId: '123',
    },
  })

  // Retrieve active sandboxes and inspect their metadata.
  const page = await Sandbox.list()
  const active = await page.nextItems()

  console.log(active[0].metadata)
  // Example output:
  // { userId: '123' }
  ```

  ```python Python icon="python" theme={"system"}
  from novita_sandbox.core import Sandbox

  # Start a sandbox and attach custom metadata.
  sbx = Sandbox.create(
      metadata={
          "userId": "123",
      },
  )

  # Retrieve active sandboxes and inspect their metadata.
  page = Sandbox.list()
  active = page.next_items()

  print(active[0].metadata)
  # Example output:
  # {"userId": "123"}
  ```
</CodeGroup>

## Metadata-based filtering

Sandboxes can also be filtered using metadata when listing.