2026.6.3
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Start app

Use this action to start an installed appApps are additional standalone third-party software packages that can be installed on Home Assistant OS. [Learn more]. A common use is to start an app only when you need it, for example starting a download client in the evening and stopping it again in the morning.

Using this action from the user interface

If you prefer building automations and scripts visually, Home Assistant walks you through this action step by step. You pick what to target, tweak a few options, and save. No YAML knowledge required.

To start an app from an automation or a script:

  1. Go to Settings > Automations & scenes.
  2. Open an existing automation or script, or select Create automation > Create new automation.
  3. If you’re setting up a new automation, add a trigger in the When section. Scripts don’t need a trigger. They run when something else calls them.
  4. In the Then do section, select Add action.
  5. Search for and select Start app.
  6. Select the App to start.
  7. Select Save.

Options in the UI

App (Required)

The app to start.

Using this action in YAML

If you work directly in YAML, or you want to know exactly what Home Assistant does under the hood, this section has the technical reference. It lists the field names you use in YAML, their types, and which ones are required.

In YAML, refer to this action as hassio.app_start. A basic example looks like this:

ActionActions are used in several places in Home Assistant. As part of a script or automation, actions define what is going to happen once a trigger is activated. In scripts, an action is called *sequence*. [Learn more] 
action: hassio.app_start
data:
  app: core_ssh

Use the slug of the app, which you can find on the app’s page under Settings > Add-ons.

Options in YAML

app string Required

The slug of the app to start.

Good to know

  • Only administrators can run this action.
  • This action is only available when you run Home Assistant Operating SystemHome Assistant OS, the Home Assistant Operating System, is an embedded, minimalistic, operating system designed to run the Home Assistant ecosystem on single board computers (like the Raspberry Pi) or Virtual Machines. It includes Home Assistant Core, the Home Assistant Supervisor, and supports apps. Home Assistant Supervisor keeps it up to date, removing the need for you to manage an operating system. Home Assistant Operating System is the recommended installation type for most users. or the Supervised installation method. It is not available on Home Assistant ContainerHome Assistant Container is a standalone container-based installation of Home Assistant Core. Any OCI compatible runtime can be used, but the documentation focus is on Docker. [Learn more] or Home Assistant CoreHome Assistant Core is the Python program at the heart of Home Assistant. It is part of all installation types. It can be installed standalone (without Home Assistant Supervisor) as a container using Docker (this is typically referred to as the Home Assistant Container installation type). For development, Core can also be run using a Virtual Environment (previously referred as the Home Assistant Core installation type). For production setup, the Home Assistant Core installation type is deprecated..

More examples

Real scenarios where this action shows up in automations and scripts. Copy any example and adapt it to your setup.

Tip

You don’t need to edit YAML to use these examples. Copy a YAML snippet from this page, open the automation editor in Home Assistant, and press Ctrl+V (or Cmd+V on Mac). Home Assistant automatically converts the pasted YAML into the visual editor format, whether it’s a full automation, a single trigger, a condition, or an action.

Automation: start a download app in the evening

Start a download client at night, when your internet connection is quieter.

  • Trigger: Time, at 23:00
  • Action: Start app
Show example YAML
AutomationAutomations in Home Assistant allow you to automatically respond to things that happen in and around your home. [Learn more] 
alias: "Start downloads at night"
triggers:
  - trigger: time
    at: "23:00:00"
actions:
  - action: hassio.app_start
    data:
      app: a0d7b954_transmission

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with the action you’re calling and what you expected to happen, or share on our subreddit /r/homeassistant.

Tip

AI assistants like ChatGPT or Claude can also explain actions or suggest the right one when you describe what you want in plain language.

Related actions

These actions work well alongside this one: