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

# Toolbar

> zopio uses the Vercel Toolbar to allow you to override feature flags in development.

The [Vercel Toolbar](https://vercel.com/docs/workflow-collaboration/vercel-toolbar) is a tool that allows you to leave feedback, navigate through important dashboard pages, share deployments, use Draft Mode for previewing unpublished content, and Edit Mode for editing content in real-time. `zopio` has the Vercel Toolbar enabled by default.

## Link your applications

Go into each application and run `vercel link`, like so:

<CodeGroup>
  ```sh app theme={"system"}
  cd apps/app
  vercel link
  ```

  ```sh web theme={"system"}
  cd apps/web
  vercel link
  ```

  ```sh api theme={"system"}
  cd apps/api
  vercel link
  ```
</CodeGroup>

This will create a `.vercel/project.json` file in each application.

## Add the environment variable

Then, simply add a `FLAGS_SECRET` environment variable to each application's `.env.local` file, like so:

```js .env.local theme={"system"}
FLAGS_SECRET="test"
```

These two steps are optional, but they are recommended to ensure that the Vercel Toolbar is enabled in each application.