> For the complete documentation index, see [llms.txt](https://fredhopper.gitbook.io/product-discovery/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://fredhopper.gitbook.io/product-discovery/building-the-front-end-experience-with-xo/readme-first.md).

# What is the XO Recommendations API

This documentation covers everything you need to know on how to use and implement XO recommendations.

## Pre-requisites

In order to benefit from the XO Recommendations API, some pre-requisites are needed:

* You have an XO account
* Your items catalog is loaded on XO. Our implementation guide is available here:

{% content-ref url="/pages/j4SREaK9igBrF8zHNcMf" %}
[Sending and Managing Product Data](/product-discovery/sending-and-managing-product-data/what-is-the-items-api.md)
{% endcontent-ref %}

* You are collecting your customers' data using the front-end tracker. Our Quickstart guide is available here:

{% content-ref url="/pages/uj3zhzLtWYXHnPYnZbZB" %}
[Tracking and Sending Events](/product-discovery/tracking-and-sending-events/sending-events.md)
{% endcontent-ref %}

Any questions? Feel free to reach out!