> ## Documentation Index
> Fetch the complete documentation index at: https://product-discovery.developer.voyado.com/llms.txt
> Use this file to discover all available pages before exploring further.
# App preview integration
> How to implement app preview mode in a Voyado Elevate site integration.
The Elevate App offers an extended on-site feature set for merchandisers when fully integrated.
Several features in the [Experience app](https://help.elevate.voyado.com/hc/en-gb/articles/27611266063132-Settings#preview-and-publish-settings) include a preview function. This allows a user to change and test settings, product selections, and more before publishing them to a live site. To preview something from the apps, a preview URL is required. For the apps, base URLs can be set in the [Admin app](https://help.elevate.voyado.com/hc/en-gb/articles/28013347219356-The-Admin-tab) , or a URL can be entered in the interface for each preview.
Preview mode can be directly accessed through the [Storefront API](/elevate/docs/api/storefront/overview) by the aid of a `viewId` parameter. All page queries accept a `viewId` parameter, which can take two different values: `production` and `preview`. The `viewId` defaults to `production` if it is omitted in a page query, so in practice the parameter should only be used for previewing purposes, that is, when in preview mode.
When clicking a Preview link in the Apps, a new browser tab is opened with the URL that is to be previewed. The URL is also appended with `?PREVIEW=true`.
## Implementation
Preview mode with the API should be implemented so that it is compatible with the app preview actions.
* Whenever `?PREVIEW=true` is encountered in the URL, requests to Elevate should be sent with `viewId=preview`.
* **Recommended.** Persist the `viewId` parameter with the value `preview` when in preview mode to enable a user to navigate pages and still see everything with preview content.
* **Recommended.** Implement a visual indicator to show the user that preview mode is active. For reference, see the image below.
* **Recommended.** Implement a toggle that allows the user to manually exit preview mode. For reference, see the image below.
* **Optional.** Restrict access to preview mode with, for example, a custom login that only enables functionality for certain levels of user access when logged in.
