# Unavailable

> A special state for an entity that Home Assistant can't reach right now. Its counterpart, unknown, means it can be reached but has no value yet.

Source: https://contributors.home-assistant.io/glossary/unavailable/

- In code: `STATE_UNAVAILABLE`, `STATE_UNKNOWN`, `available`
- Also: unknown

An integration marks its entities as unavailable when the device is offline or the API fails, by setting `available` to `False`. It never reports a made-up value instead.

## Related terms

- [State](https://contributors.home-assistant.io/glossary/state/): The current value of an entity, like `on`, `21.5`, or `playing`, together with its attributes.
- [Coordinator](https://contributors.home-assistant.io/glossary/coordinator/): A helper that fetches data for many entities at once, on a schedule, so a device or API is asked once instead of once per entity.