Start Time for Home Assistant

A custom Home Assistant integration that exposes Home Assistant's own boot initialization time as a sensor.

Features

• A Start Time sensor reporting the boot time in seconds — the same value Home Assistant logs at startup (Home Assistant initialized in 25.5s).
• Per-integration setup durations exposed as sensor attributes, sorted from slowest to fastest — handy for spotting what slows your startup down.
• Works independently of your logger component settings.

Requirements

• Home Assistant 2025.1 or newer
• Python 3.13 or newer

Installation

HACS (recommended)

1. Open HACS in Home Assistant.
2. Open the menu (top-right) → Custom repositories.
3. Add foXaCe/StartTime with the category Integration.
4. Search for Start Time and install it.
5. Restart Home Assistant.
6. Go to Settings → Devices & Services → Add Integration → Start Time.

Manual

1. Copy the custom_components/start_time/ folder into your <config>/custom_components/ folder.
2. Restart Home Assistant.
3. Add the integration from the UI.

Configuration

Go to Settings → Devices & Services → Add Integration → Start Time.

There is nothing to configure. If the integration does not appear in the list, clear your browser cache and try again.

The sensor

• State: the boot initialization time, in seconds.
• Attributes: per-integration setup durations, sorted slowest first.

How it works

Home Assistant reports its initialization time in the INFO logs. This integration surfaces the same value as a sensor:

2020-02-24 17:13:11 INFO (MainThread) [homeassistant.bootstrap] Home Assistant initialized in 25.5s

This is useful for debugging startup performance on slow hardware such as a Raspberry Pi.

Example automations

Get notified when Home Assistant took unusually long to start:

automation:
  - alias: "Notify on slow startup"
    triggers:
      - trigger: numeric_state
        entity_id: sensor.start_time
        above: 60
    actions:
      - action: notify.persistent_notification
        data:
          title: "Slow startup"
          message: >-
            Home Assistant took {{ states('sensor.start_time') }} seconds
            to start.

The per-integration setup durations are available as attributes, so you can watch a specific integration:

{{ state_attr('sensor.start_time', 'recorder') }}

Known limitations

• The value is captured once per startup, when Home Assistant logs that it has finished initializing. It never changes until the next restart.
• When the integration is added to an already-running instance, the sensor shows the value restored from the previous boot (or stays unknown on the very first install) until Home Assistant is restarted.
• The capture relies on the Home Assistant initialized in X.XXs log record emitted by homeassistant.bootstrap — Home Assistant exposes this value through no public API. The test suite guards the message format on every supported release.
• Per-integration attributes are intentionally not recorded in the history database (they change on every boot and would bloat the recorder); they are always available live and in the integration diagnostics.

Removal

1. Go to Settings → Devices & Services, open Start Time and choose Delete from the entry menu.
2. Remove the files: in HACS, open Start Time and choose Remove (manual install: delete the custom_components/start_time/ folder).
3. Restart Home Assistant.

The integration keeps no leftover data: no options, no external connections, and its stored state is removed with the entity.

Contributing

Contributions are welcome — see CONTRIBUTING.md.

License

Released under the MIT License. This is a maintained fork of AlexxIT/StartTime.