> ## 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.

# Introduction to Experimental

<Warning>
  Following our new [versioning policy](https://developers.criteo.com/criteo-apis/docs/versioning-policy), the Preview tier has been replaced by Experimental. If you are currently calling Preview endpoints, you must migrate to the stable [2026.07](/retail-media/reference) version before the end of 2026.
</Warning>

## Experimental version

The experimental version lets you explore brand-new features before they are finalized, so you can plan ahead and provide early feedback.

New features may appear in the experimental version at any time and may change significantly before — or without ever — reaching a stable release.

This version can be called using "experimental" as the version identifier:

```http theme={null}
https://api.criteo.com/experimental
```

<Info>
  For more details, visit our [Versioning policy](https://developers.criteo.com/criteo-apis/docs/versioning-policy) page.
</Info>

**Experimental — For early exploration**

* Test brand-new features before they're finalized
* Contracts may change significantly at any time
* Not suitable for production use

For the stable endpoints and other detailed documentation, see the [current Criteo API version](/retail-media/docs/welcome-to-criteo).

## New unified entity model

The experimental section is where a major API redesign is being built. The goal is a single contract that works across all campaign types — replacing the separate format-specific routes with a unified set of endpoints.

The format-specific line item routes (Onsite Display, Sponsored Products, Preferred Deals) are the legacy path and are grouped accordingly in the navigation. New integrations should use the unified endpoints as support expands:

| New unified endpoint | Replaces |
| - | - |
| [Line Item Core](/retail-media/experimental/docs/line-items-core) | Type-specific line item create and update routes |
| [Line Item Targets](/retail-media/experimental/docs/line-item-targets) | Per-type targeting endpoints and scattered bid multiplier fields |
| [Line Item Creatives](/retail-media/experimental/docs/line-item-creatives) | Format-specific creative attachment and product lists |