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Events

The core of Home Assistant is the event bus. The event bus allows any integration to fire or listen for events.

Events and state changes

All entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more] produce state change events. Every time a stateThe state holds the information of interest of an entity, for example, if a light is on or off. Each entity has exactly one state and the state only holds one value at a time. However, entities can store attributes related to that state such as brightness, color, or a unit of measurement. [Learn more] changes, a state change event is produced. State change events are just one type of event on the event bus, but there are other kinds of events, such as the built-in events that are used to coordinate between various integrations.

State change events versus event entity

State change events are not to be confused with the event entity. The event entity is a specific type of entity that itself produces event state changes, just like all other entities.

Any state change will be announced on the event bus as a state_changed event, containing the previous and the new state of an entity.

Common fields

All events share these basic fields.

Field	Description
`event_type`	Type of the event. Example: `call_service`.
`origin`	Origin of the event. `REMOTE` (coming in from the API, e.g. a webhook) or `LOCAL` (everything else).
`time_fired`	When the event was fired. Example: `2022-01-28T12:19:53.736380+00:00`.
`context`	Dictionary with the context. Example: `{ 'id': '123', "parent_id": null, 'user_id': 'abc'}`.

In addition, all events contain a data dictionary with event-specific information. These are described below.

Built-in Events (core)

call_service

This event is fired when an service action is performed

Field	Description
`domain`	Domain of the action. Example: `light`.
`service`	The service action that is performed. Example: `turn_on`
`service_data`	Dictionary with the call parameters. Example: `{ 'brightness': 120 }`.
`service_call_id`	String with a unique call id. Example: `23123-4`.

component_loaded

This event is fired when a new integration has been loaded and initialized.

Please note that while this event is fired for each loaded integration during Home Assistant startup, the automation engine of Home Assistant is started last. Thus this event can not be used to run automations during startup as it would have missed these events.

Field	Description
`component`	Domain of the integration that has just been initialized. Example: `light`.

core_config_updated

This event is fired when the core configuration is updated, for example when the location has been changed.

It contains no additional data.

data_entry_flow_progressed

This event is fired when a data entry flow has changed and is used by the frontend to reload the flow state.

Field	Description
`handler`	The flow handler.
`flow_id`	Identification of the flow.

homeassistant_start, homeassistant_started

These events are fired during the startup of Home Assistant, in the following order:

homeassistant_start
homeassistant_started

These events contain no additional data.

If you want to trigger automation on a Home Assistant start event, we recommend using the special Home Assistant trigger instead of listening to these events.

homeassistant_stop, homeassistant_final_write, homeassistant_close

These events are fired during the shutdown of Home Assistant, in the following order:

homeassistant_stop
homeassistant_final_write
homeassistant_close

These events contain no additional data.

Please note that homeassistant_final_write and homeassistant_close, cannot be used with automations, as the automation engine would already have been stopped when those are fired.

If you want to trigger automation on a Home Assistant stop event, we recommend using the special Home Assistant trigger instead of listening to these events.

logbook_entry

Field	Description
`name`	Name of the entity. Example: `Kitchen light`.
`message`	Message. Example: `was turned on`
`domain`	Optional, domain of the entry. Example: `light`
`entity_id`	Optional, identifier of the entity that was logged.

service_registered

This event is fired when a new service action has been registered within Home Assistant.

Field	Description
`domain`	The domain of the integration that offers this action. Example: `light`.
`service`	The name of the service action. Example: `turn_on`

service_removed

This event is fired when a service action has been removed from Home Assistant.

Field	Description
`domain`	The domain of the integration that offers this action. Example: `light`.
`service`	The name of the service action. Example: `turn_on`

state_changed

This event is fired when a state has changed. It contains the entity identifier and both the new_state and old_state of the entity as state objects.

Field	Description
`entity_id`	Identifier of the entity that has changed. Example: `light.kitchen`
`old_state`	The previous state of the entity before it changed. Omitted if the state is set for the first time.
`new_state`	The new state of the entity. Omitted if the state has been removed.

themes_updated

This event is fired after a theme has been set or reloaded. It contains no additional data.

user_added

This event is fired when a user has been added.

Field	Description
`user_id`	Identification of the new user.

user_removed

This event is fired when a user has been removed.

Field	Description
`user_id`	Identification of the removed user.

Built-in events (default integrations)

automation_reloaded

Integration: automation

This event is fired when automations have been reloaded and thus might have changed.

This event contains no additional data.

automation_triggered

Integration: automation

This event is fired when an automation is triggered.

Field	Description
`name`	The name of the automation.
`entity_id`	The identifier of the automation.

scene_reloaded

Integration: homeassistant

This event is fired when scenes have been reloaded and thus might have changed.