Native API Component

The ESPHome native API is used to communicate with clients directly, with a highly-optimized network protocol. Currently, only the ESPHome tool and Home Assistant use this native API.

After adding an api: line to your ESPHome configuration you can go to the Home Assistant web interface and navigate to the “Integrations” screen in the “Configuration” panel. Then wait for the ESPHome device to show up under the discovered section (can take up to 5 minutes) or add the device manually by choosing “ESPHome” from the integration overview and entering “<NODE_NAME>.local” or the IP address of the unit in the “Host” field.

The ESPHome native API is based on a custom TCP protocol using protocol buffers. You can find the protocol data structure definitions here: https://github.com/esphome/esphome/blob/dev/esphome/components/api/api.proto A Python library that implements this protocol is aioesphomeapi.

# Example configuration entry
api:
  password: 'MyPassword'

Configuration variables:

  • port (Optional, integer): The port to run the API Server on. Defaults to 6053.
  • password (Optional, string): The password to protect the API Server with. Defaults to no password.
  • services (Optional, list): A list of user-defined services. See User-defined Services.
  • reboot_timeout (Optional, time): The amount of time to wait before rebooting when no client connects to the API. This is needed because sometimes the low level ESP functions report that the ESP is connected to the network, when in fact it is not - only a full reboot fixes it. Can be disabled by setting this to 0s. Defaults to 15min.
  • id (Optional, ID): Manually specify the ID used for code generation.

homeassistant.service Action

When using the native API with Home Assistant, you can create Home Assistant service calls straight from ESPHome Automations.

# In some trigger
on_...:
  # Simple
  - homeassistant.service:
      service: notify.html5
      data:
        title: Button was pressed
  # With templates and variables
  - homeassistant.service:
      service: notify.html5
      data:
        title: New Humidity
      data_template:
        message: The humidity is {{ my_variable }}%.
      variables:
        my_variable: |-
          return id(my_sensor).state;

Configuration options:

  • service (Required, string): The Home Assistant Service to call.
  • data (Optional, mapping): Optional static data to pass along with the service call.
  • data_template (Optional, mapping): Optional template data to pass along with the service call. This is evaluated on the Home Assistant side with Home Assistant’s templating engine.
  • variables (Optional, mapping): Optional variables that can be used in the data_template. Values are lambdas and will be evaluated before sending the request.

User-defined Services

It is also possible to get data from Home Assistant to ESPHome with user-defined services. When you declare services in your ESPHome YAML file, they will automatically show up in Home Assistant and you can call them directly.

# Example configuration entry
api:
  services:
    - service: start_laundry
      then:
        - switch.turn_on: relay
        - delay: 3h
        - switch.turn_off: relay

For example with the configuration seen above, after uploading you will see a service called esphome.livingroom_start_laundry (livingroom is the node name) which you can then call.

Additionally, you can also transmit data from Home Assistant to ESPHome with this method:

# Example configuration entry
api:
  services:
    - service: start_effect
      variables:
        my_brightness: int
        my_effect: string
      then:
        - light.turn_on:
            id: my_light
            brightness: !lambda 'return my_brightness;'
            effect: !lambda 'return my_effect;'

Using the variables key you can tell ESPHome which variables to expect from Home Assistant. For example the service seen above would be executed with something like this:

# Example Home Assistant Service Call
service: esphome.livingroom_start_effect
data_template:
  my_brightness: "{{ states.brightness.state }}"
  my_effect: "Rainbow"

Then each variable you define in the variables section is accessible in the automation triggered by the user-defined service through the name you gave it in the variables section (note: this is a local variable, so do not wrap it in id(...) to access it).

There are currently 4 types of variables:

  • bool: A boolean (ON/OFF). C++ type: bool
  • int: An integer. C++ type: int/int32_t
  • float: A floating point number. C++ type: float
  • string: A string. C++ type: std::string

Each of these also exist in array form:

  • bool[]: An array of boolean values. C++ type: std::vector<bool>
  • … - Same for other types.

api.connected Condition

This Condition checks if at least one client is connected to the ESPHome native API. Please note client not only includes Home Assistant, but also ESPHome’s OTA log output if logs are shown remotely.

on_...:
  if:
    condition:
      api.connected:
    then:
      - logger.log: API is connected!

Advantages over MQTT

The ESPHome native API has many advantages over using MQTT for communication with Home Automation software (currently only Home Assistant). But MQTT is a great protocol and will never be removed. Features of native API (vs. MQTT):

  • Much more efficient: ESPHome encodes all messages in a highly optimized format with protocol buffers - for example binary sensor state messages are about 1/10 of the size.
  • One-click configuration: ESPHome just needs one click to set up in Home Assistant - no more messing around with retained MQTT discovery messages and alike.
  • One less single point of failure: In the ESPHome native API each ESP is its own server. With MQTT, when the broker shuts off nothing can communicate anymore.
  • Stability: Since ESPHome has far more control over the protocol than with MQTT, it’s really easy for us to roll out stability improvements.
  • Low Latency: The native API is optimized for very low latency, usually this is only a couple of milliseconds and far less than can be noticed by the eye.

homeassistant.event Action

When using the native API with Home Assistant, you can create events in the Home Assistant event bus straight from ESPHome Automations.

# In some trigger
on_...:
  # Simple
  - homeassistant.event:
      event: esphome.button_pressed
      data:
        title: Button was pressed

Configuration options:

  • event (Required, string): The event to create - must begin with esphome.
  • data (Optional, mapping): Optional static data to pass along with the event.
  • data_template (Optional, mapping): Optional template data to pass along with the event. This is evaluated on the Home Assistant side with Home Assistant’s templating engine.
  • variables (Optional, mapping): Optional variables that can be used in the data_template. Values are lambdas and will be evaluated before sending the request.