> For the complete documentation index, see [llms.txt](https://developer.collibra.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.collibra.com/api/guides/import-api/synchronization/synchronization-id.md).

# Synchronization ID

You must specify a synchronization ID for all the synchronization API calls. The ID is used to uniquely identify the external source and is assigned to all the resources imported during a synchronization process. The Synchronization API tracking system relies on the synchronization ID to efficiently identify resources that need to be removed.

{% hint style="success" %}
Although there is no predefined format for the synchronization ID, it should clearly identify the external source.
{% endhint %}