# Preview locally (/cli/preview)

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Related: [Install the CLI](/cli/install.md), [Mintlify CLI command reference](/cli/commands.md)

## Prerequisites [#prerequisites]

* The [Mintlify CLI](/cli/install) installed globally, or run commands with `npx mint`.
* A documentation directory with a valid `docs.json` file.

## Start the local preview [#start-the-local-preview]

Navigate to your documentation directory containing your `docs.json` file and run:

```bash
mint dev
```

The local preview starts at `http://localhost:3000`. As you edit, changes appear in real time.

By default, the preview opens automatically in your browser. To prevent the browser from opening, use the `--no-open` flag:

```bash
mint dev --no-open
```

To generate a preview without installing the CLI globally, run:

```bash
npx mint dev
```

## Log in for search and assistant [#log-in-for-search-and-assistant]

You must authenticate the CLI with your Mintlify account to enable search and the [assistant](/assistant/index).

```bash
mint login
```

After you authenticate with the `mint login` command, the CLI stores your credentials in `~/.config/mintlify/config.json` so you stay logged in across sessions. The CLI also prompts you to select a default project, which commands like `mint automations` use.

Once logged in, run `mint dev` to start the local preview with search and the assistant enabled. The assistant uses the same indexed content as your deployed documentation site.

To check your authentication status, run:

```bash
mint status
```

To log out, run:

```bash
mint logout
```

## Custom ports [#custom-ports]

By default, the CLI uses port 3000. To use a different port, use the `--port` flag:

```bash
mint dev --port 3333
```

If the port is already in use, the CLI automatically tries the next available port.

## Skip OpenAPI processing [#skip-openapi-processing]

If you have many OpenAPI files, skip OpenAPI processing during local development to improve performance with the `--disable-openapi` flag:

```bash
mint dev --disable-openapi
```

## Disable navigation prefetching [#disable-navigation-prefetching]

By default, the local preview prefetches nearby pages to optimize page load speeds. For very large sites, this can slow down the page you are actively viewing if many pages compile in the background at the same time.

If you have thousands of pages and notice slow page loads during local preview, disable prefetching with the `--disable-prefetch` flag:

```bash
mint dev --disable-prefetch
```

With prefetching disabled, pages compile only when you navigate to them. Individual page loads take longer than a prefetched page, but the page you request is not competing with background compilation.

## Preview as a specific group [#preview-as-a-specific-group]

If you use group-based access control, preview as a specific authentication group with the `--groups` flag:

```bash
mint dev --groups admin
```

See [Authentication setup](/deploy/authentication-setup#control-access-with-groups) for more information on groups.