# Add an optional dependency (/docs/guides/install/add-optional)

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Related: [Add a dependency](/docs/guides/install/add.md), [Add a development dependency](/docs/guides/install/add-dev.md), [Add a peer dependency](/docs/guides/install/add-peer.md), [Add a Git dependency](/docs/guides/install/add-git.md), [Add a tarball dependency](/docs/guides/install/add-tarball.md), [Install a package under a different name](/docs/guides/install/npm-alias.md)

To add an npm package as an optional dependency, use the `--optional` flag.

```sh terminal icon="terminal"
bun add zod --optional
```

***

This adds the package to `optionalDependencies` in `package.json`.

```json package.json icon="file-json"
{
  "optionalDependencies": {
    "zod": "^3.0.0" // [!code ++]
  }
}
```

***

See [`bun install`](/pm/cli/install).