> For the complete documentation index, see [llms.txt](https://developer.mediarithmics.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.mediarithmics.io/user-points/user-identifiers/networks-ids/user-based-network-ids/custom-user-id-integration.md).

# Custom User ID integration

Custom User IDs are used to identify your users with your systems such as CRMs, loyalty programs, or authentication systems.

### Create a Custom User ID

1. Go to **Navigator > Settings > Organisation > Compartments**.
2. In the **First-party user account compartments** section, click on **New Compartment**.
3. Specify the following details:

| Parameters | Description                                                         |
| ---------- | ------------------------------------------------------------------- |
| Name       | Name of the Compartment                                             |
| Token      | A technical identifier used to link the Compartment with the JS Tag |

If you have multiple datamarts, don't forget to activate the new Compartment on all other datamarts.


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