> ## Documentation Index
> Fetch the complete documentation index at: https://payload-plugin-openapi.seshuk.im/llms.txt
> Use this file to discover all available pages before exploring further.

# Metadata

> The metadata object sets the API title, version, and description written to the spec info block.

`metadata` fills the `info` block of the generated document. It is the only required plugin option.

```ts payload.config.ts theme={null}
openapi({
  metadata: {
    title: 'My API',
    version: '1.0.0',
    description: 'Public API for the example app.',
  },
})
```

| Option        | Type     | Default | Description                                |
| ------------- | -------- | ------- | ------------------------------------------ |
| `title`       | `string` | —       | API title. **Required.**                   |
| `version`     | `string` | —       | Your API's version. **Required.**          |
| `description` | `string` | —       | Optional description for the `info` block. |

<Warning>`metadata.title` and `metadata.version` are required. The plugin throws on boot if either is missing.</Warning>

## The base URL is not metadata

`metadata` carries the API's title, version, and description only — never its URL. Keeping the base URL out of the config is what lets the same document work behind any host, proxy, or environment.

* **Over HTTP**, the spec's `servers` field is filled in per request from the incoming `Host` header. There is nothing to configure.
* **Writing to a file**, there is no request to read a host from, so you set it yourself with the CLI's `--server` flag (see [Generate](/cli/generate)) or an explicit `servers` array when building the document in your own code (see [Programmatic use](/guides/programmatic-use)).