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

# Sync Ziik users with your own system

> Two-way sync using the reference field to link Ziik users to your external system.

Use the **reference** field to link Ziik users to records in your own system (e.g. employee ID, HR system key). This enables two-way sync:

* **Your system → Ziik:** When creating or updating users via the API, set `reference` to your external identifier. You can later look up that user in Ziik with `GET /users/reference/{reference}`.
* **Ziik → your system:** When listing or fetching users from Ziik, each user's `reference` is returned. Use it to match and update the corresponding record in your system.

Keep `reference` unique and stable so you can reliably resolve users in both directions and avoid duplicates.