A feature flag can have only one parent dependency but multiple child flags can share the same parent. For a child flag to be activated, its parent dependency must be satisfied.
* **Parent Value**: Parent value should match predefined feature status and variant criteria.
### Parent value criteria
In order for the child feature to be evaluated, the corresponding parent value criteria must be satisfied.
Parent value criteria can be set to one of the 3 options:
* parent feature must be **enabled**.
* parent feature must be **disabled**. This is useful when your parent is a [kill-switch](./feature-toggle-types.md#feature-toggle-types) with the inverted enabled/disabled logic.
* parent feature must be **enabled with variants**. This is useful when your parent is part of A/B testing, and you need **variant dependencies**.
For the **variant dependencies**, if the parent feature variant is evaluated to the expected value, the dependency is satisfied.
You can specify variant values from all [strategy variants](./strategy-variants.md) and all [feature environment variants](./feature-toggle-variants.md). The parent dependency variant
is compared to the actual value that the parent dependency is evaluated to in a given environment.
Consult [strategy variants order](./strategy-variants.md#strategy-variants-and-strategies-order) and [variants comparison](./strategy-variants#strategy-variants-vs-feature-toggle-variants) sections for more details on the variant evaluation order.
Introduce dependencies either through the UI or API, also applicable when copying a child feature with an existing parent dependency.
### Removing
Eliminate them through the UI or API. Dependencies are also removed when archiving a child feature. A parent feature can’t be removed if it would leave a child feature orphaned. To remove both, batch archive them. If Unleash confirms no other child features are using the parent, archiving proceeds.
## Permissions
The **Update feature dependency** project permission, auto-assigned to admin and project members, allows managing dependencies.
## Metrics calculation
Metrics are influenced solely by the evaluation of child features.
## Client SDK Support {#client-sdk-support}
To make use of dependent feature, you need to use a compatible client. Client SDK with variant support:
- Client SDKs talking to [unleash-proxy](https://github.com/Unleash/unleash-proxy) (from v0.18.0)
- Client SDKs talking to [unleash-edge](https://github.com/Unleash/unleash-edge) (from v13.1.0)
- Client SDKs talking to Frontend API in [unleash-server](https://github.com/Unleash/unleash) (from v5.7.0)
- Unleash Playground in [unleash-server](https://github.com/Unleash/unleash) (from v5.7.0)
If you would like to give feedback on this feature, experience issues or have questions, please feel free to open an issue on [GitHub](https://github.com/Unleash/unleash/).
