Connect to a printer

Use this action to tell your OctoPrint server to connect to a printer. You can let OctoPrint pick the connection settings automatically, or specify a printer profile, serial port, and baud rate.

This is handy in automations, for example to reconnect to your printer automatically after the server reboots, so it is ready to start a print without manual steps.

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 connect to a printer 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. From the search box, search for and select OctoPrint: Connect to a printer.
6. Select the Server that should connect. Optionally, set a profile name, serial port, and baud rate.
7. Select Save.

Options in the UI

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 octoprint.printer_connect. A basic example looks like this:

action: octoprint.printer_connect
data:
  device_id: a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4

This tells the selected OctoPrint server to connect to its printer using the automatic connection settings.

Options in YAML

Good to know

• When you leave the profile name, serial port, and baud rate empty, OctoPrint uses its automatic connection settings.

Try it yourself

Ready to test this? Open Developer tools > Actions, search for this action, fill in the fields, and select Perform action. You see what happens on your actual 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] without writing a line of YAML.

More examples

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

Automation: reconnect to the printer after the server reboots

When the OctoPrint server comes back online, tell it to connect to the printer so it is ready for the next print.

• Trigger: The OctoPrint server becomes available
• Action: OctoPrint: Connect to a printer

alias: "Reconnect OctoPrint to the printer"
triggers:
  - trigger: state
    entity_id: binary_sensor.octoprint_printing
    from: "unavailable"
actions:
  - action: octoprint.printer_connect
    data:
      device_id: a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4

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.