Home Assistant REST API Reference

Authentication

All requests require the Authorization header:

Authorization: Bearer <long-lived-access-token>

Base Endpoints

Endpoint	Method	Description
`/api/`	GET	API status and HA version
`/api/config`	GET	Current configuration
`/api/states`	GET	All entity states
`/api/states/<entity_id>`	GET	Single entity state
`/api/states/<entity_id>`	POST	Set entity state
`/api/services`	GET	Available services
`/api/services/<domain>/<service>`	POST	Call a service
`/api/events`	GET	Available events
`/api/events/<event_type>`	POST	Fire an event
`/api/history/period/<timestamp>`	GET	State history
`/api/logbook/<timestamp>`	GET	Logbook entries

Common Services

Lights

# Turn on with options
POST /api/services/light/turn_on
{
  "entity_id": "light.living_room",
  "brightness": 255,           # 0-255
  "color_temp": 370,           # Mireds (153-500 typically)
  "rgb_color": [255, 0, 0],    # RGB array
  "transition": 2              # Seconds
}

# Turn off
POST /api/services/light/turn_off
{"entity_id": "light.living_room"}

Climate

# Set temperature
POST /api/services/climate/set_temperature
{
  "entity_id": "climate.thermostat",
  "temperature": 22,
  "hvac_mode": "heat"  # heat, cool, auto, off
}

# Set preset
POST /api/services/climate/set_preset_mode
{
  "entity_id": "climate.thermostat",
  "preset_mode": "away"
}

Media Player

# Play/pause
POST /api/services/media_player/media_play_pause
{"entity_id": "media_player.tv"}

# Set volume (0.0-1.0)
POST /api/services/media_player/volume_set
{"entity_id": "media_player.tv", "volume_level": 0.5}

# Play media
POST /api/services/media_player/play_media
{
  "entity_id": "media_player.tv",
  "media_content_type": "music",
  "media_content_id": "spotify:playlist:xyz"
}

Cover (Blinds/Garage)

POST /api/services/cover/open_cover
{"entity_id": "cover.garage"}

POST /api/services/cover/close_cover
{"entity_id": "cover.garage"}

POST /api/services/cover/set_cover_position
{"entity_id": "cover.blinds", "position": 50}  # 0=closed, 100=open

Notifications

POST /api/services/notify/mobile_app_phone
{
  "message": "Motion detected!",
  "title": "Security Alert",
  "data": {
    "image": "/local/camera_snapshot.jpg"
  }
}

Entity State Object

{
  "entity_id": "light.living_room",
  "state": "on",
  "attributes": {
    "brightness": 255,
    "color_temp": 370,
    "friendly_name": "Living Room Light",
    "supported_features": 63
  },
  "last_changed": "2024-01-15T10:30:00+00:00",
  "last_updated": "2024-01-15T10:30:00+00:00"
}

Webhooks (Inbound to HA)

Trigger automations via webhook:

POST /api/webhook/<webhook_id>
{"custom": "data"}

Create webhook trigger in automation:

automation:
  trigger:
    - platform: webhook
      webhook_id: my_webhook_id
      allowed_methods:
        - POST

WebSocket API

For real-time updates, use the WebSocket API at ws://ha-url/api/websocket.

Connection flow:

Connect to WebSocket
Receive auth_required
Send {"type": "auth", "access_token": "TOKEN"}
Receive auth_ok
Subscribe to events: {"id": 1, "type": "subscribe_events", "event_type": "state_changed"}

Error Responses

Code	Meaning
400	Bad request (invalid JSON or missing fields)
401	Unauthorized (invalid/missing token)
404	Entity or service not found
405	Method not allowed

Rate Limits

Home Assistant doesn't enforce strict rate limits, but avoid:

Polling faster than every 1 second
Bulk updates without batching

Use WebSocket for real-time state tracking instead of polling.

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