> For the complete documentation index, see [llms.txt](https://help.citrusad.com/retail-media-interface/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.citrusad.com/retail-media-interface/partner/partner-api-authentication/authenticating-requests.md).
# Authentication requests
Epsilon Retail Media uses the User Key method for authenticating API requests. You can also retrieve the User Key through the [Retrieve user key](/retail-media-interface/partner/partner-api-authentication/getuserkey.md) API, which serves as an alternate method to obtain the User Key from user settings. The Retrieve user key API allows partners to generate an authentication key by providing a valid username and password.
## User key
In the Epsilon Retail Media platform, advertisers can find their user key in the **User Settings** section. This key is unique to a **user** level, and can be integrated into your application to manage authentication with the Epsilon Retail Media system.
{% hint style="warning" %}
This user key is not representative of a team, and should not be treated as such.
{% endhint %}
### Authentication flow diagram
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