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

# Prerequisites

> What you need before embedding a CBS widget or calling the calculators API: your key, supported browsers, and hosting.

Before you start with [widgets](/cbs/getting-started/embed-widget) or the [calculators API](/cbs/getting-started/call-api), make sure you have the following.

## Your key

CBS uses a **single key** for both integration paths:

* **Widgets:** pass the key in the script tag's `src`:

  ```html theme={null}
  <script src="…/salary.js?key=yourKey"></script>
  ```
* **Calculators API:** send the *same* value in the `pcc-api-key` request header:

  ```http theme={null}
  pcc-api-key: yourKey
  ```

It's one credential: the widget reads the key from its own script tag and forwards it to the API as `pcc-api-key`.

To request a key or retrieve an existing one, contact your Symmetry Client Success representative or reach out through the [Client Support Center](https://support.symmetry.com).

## Supported browsers (widgets)

CBS widgets run in current versions of the major browsers (Chrome, Edge, Firefox, Safari). **Internet Explorer is not supported**: the widget shows an unsupported-browser message instead of loading.

<Note>
  There is no formal minimum-version matrix; any modern, evergreen browser works.
</Note>

## Hosting

* **Widgets:** must load from a web server over `http(s)://`, not opened directly from the local file system (`file://`). A widget reads its host from its own script URL, so it needs a live page URL to render.
* **Calculators API:** always accessed over **HTTPS**.

## Key limits and restrictions

* **Domain restriction:** a key can be limited to specific domains, so it only works on sites you control. See [Authentication model](/cbs/core-concepts/authentication-model).
* **Trial key cap:** trial keys have a calculation limit. Once it's reached, the API returns a 401 error ("API rate limit has been exceeded"). See [Rate limits](/cbs/api/rate-limits).

## Next

<CardGroup cols={2}>
  <Card title="Quickstart: Embed a widget" icon="rocket" href="/cbs/getting-started/embed-widget">
    Add a calculator to a page with one script tag.
  </Card>

  <Card title="Quickstart: Call the calculators API" icon="rocket" href="/cbs/getting-started/call-api">
    Authenticate and run your first calculation.
  </Card>
</CardGroup>