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

# Ad Request Best Practices

## Use of Filters

Retailers can enhance the user experience by **integrating filters in Ad requests** when a user selects a filter onsite. Any time a user selects a filter, **a new API call should be made to Criteo including that filter**.

<Check>
  **Benefit**

  This ensures the most relevant ad is presented to the user.
</Check>

***

## Region-specific Data

For sites that allow users to select a specific store with limited product availability, retailers should pass the corresponding store ID in the ad request when a user is browsing a specific store.

<Check>
  **Benefit**

  Ads will only showcase products available at the selected store, improving relevance.
</Check>

***

## Blocking Ads on Specific Pages

If a retailer needs to exclude certain pages (e.g., by keyword, category, or context) from ad serving, the recommended approach is to request a new `pageID` with no placements configured. That `pageID` should then be used specifically on the pages where ads should not appear.

<Check>
  **Benefit**

  This method cleanly separates ad-eligible and ad-excluded pages, avoiding the need for in-page filtering logic.
</Check>

***

<br />

## What's next

* [Formats overview](/retailer-integration/docs/format-overview)