Segments can be created, edited, and deleted from the segments page in the admin UI or via the API (see the [segments API documentation](../api/admin/segments.mdx)).
A segment that is in use **cannot** be deleted. If you'd like to delete a segment that is in use, you must first remove the segment from all the activation strategies that are currently using it.
[image of the segments page and the segments item in the menu?]
## When to use segments
Segments let you create user groups based on data available in the Unleash context.
These groups can be as simple or complex as you want to make them.
You could, for example, use segments to target:
- Users in a specific region
- Users on a specific device type
- Users who signed up before a specific point in time
or any combination thereof. Because segments stay in sync across strategies, any changes will propagate to all the activation strategies that use them.
If you need to keep time-based feature availability in sync across, you can use segments to achieve this too. For instance, you could create a "Black Friday" segment which is only satisfied on that specific Friday and use that to synchronize the availability of a number of related features.
