State Objects

Your devices are represented in Home Assistant as entities. The entities will write their current state to the state machine for other entities/templates/frontend to access. States are a current representation of the entity.

If you overwrite a state via the states dev tool or the API, it will not impact the actual device. If the device state is being polled, it will overwrite the state in the state machine the next polling.

All states will always have an entity id, a state and a timestamp when last updated and last changed.

Field Description
state.state String representation of the current state of the entity. Example off.
state.entity_id Entity ID. Format: <domain>.<object_id>. Example:
state.domain Domain of the entity. Example: light.
state.object_id Object ID of entity. Example: kitchen. Name of the entity. Based on friendly_name attribute with fall back to object ID. Example: Kitchen Ceiling.
state.last_updated Time the state was written to the state machine in UTC time. Note that writing the exact same state including attributes will not result in this field being updated. Example: 2017-10-28 08:13:36.715874+00:00.
state.last_changed Time the state changed in the state machine in UTC time. This is not updated when there are only updated attributes. Example: 2017-10-28 08:13:36.715874+00:00.
state.attributes A dictionary with extra attributes related to the current state.
state.context A dictionary with extra attributes related to the context of the state.


The attributes of an entity are optional. There are a few attributes that are used by Home Assistant for representing the entity in a specific way. Each integration will also have its own attributes to represent extra state data about the entity. For example, the light integration has attributes for the current brightness and color of the light. When an attribute is not available, Home Assistant will not write it to the state.

When using templates, attributes will be available by their name. For example state.attributes.assumed_state.

Attribute Description
friendly_name Name of the entity. Example: Kitchen Ceiling.
icon Icon to use for the entity in the frontend. Example: mdi:home.
entity_picture URL to a picture that should be used instead of showing the domain icon. Example:
assumed_state Boolean if the current state is an assumption. More info Example: True.
unit_of_measurement The unit of measurement the state is expressed in. Used for grouping graphs or understanding the entity. Example: °C.

When an attribute contains spaces, you can retrieve it like this: state_attr('sensor.livingroom', 'Battery numeric').


Context is used to tie events and states together in Home Assistant. Whenever an automation or user interaction causes states to change, a new context is assigned. This context will be attached to all events and states that happen as result of the change.

Field Description
context_id Unique identifier for the context.
user_id Unique identifier of the user that started the change. Will be None if action was not started by a user (ie. started by an automation)
parent_id Unique identifier of the parent context that started the change, if available. For example, if an automation is triggered, the context of the trigger will be set as parent.