Skip to content

Slicer Uploads

Most popular slicers can upload G-code files directly to your printer. This works through Moonraker's OctoPrint compatibility layer — your slicer thinks it is talking to OctoPrint, and Moonraker translates the requests.

Prerequisites

Add the [octoprint_compat] section to your moonraker.conf and restart Moonraker. Without this, slicer uploads will not work. See the Moonraker configuration for a complete example.

moonraker.conf
[octoprint_compat]

OrcaSlicer

  1. Open Printer Settings.
  2. In the Connection section, set Host Type to OctoPrint.
  3. Enter your printer URL in the Hostname, IP or URL field — for example http://printer.local or http://192.168.1.100.
  4. Enter any non-empty string in the API Key field — the value is not validated.
  5. Click Test to verify the connection.

After slicing, use the Print or Send button to upload directly to your printer.

PrusaSlicer / SuperSlicer

  1. Open Printer Settings and click the cog icon next to the printer profile dropdown.
  2. Select Add physical printer.
  3. Enter a descriptive name and choose the correct printer preset.
  4. Set the type to OctoPrint.
  5. Enter your printer URL in the Hostname, IP or URL field — for example printer.local or 192.168.1.100. You may need to append the Moonraker port (e.g. :7125) depending on your setup.
  6. Enter any non-empty string in the API Key field.
  7. Click Test to verify the connection.

screenshot screenshot

Cura

Install the OctoPrint Connection plugin from the Cura Marketplace. Then:

  1. Open Settings and select OctoPrint under Printers.
  2. Click Add and enter your printer URL — for example http://printer.local or http://192.168.1.100.
  3. Enter any non-empty string in the API Key field.
  4. Click Connect to verify.

After slicing, use the Print with OctoPrint button to upload.

Troubleshooting

Connection refused

  • Verify Moonraker is running — try opening http://<your-printer>/server/info in a browser.
  • Check that [octoprint_compat] is present in moonraker.conf and that Moonraker has been restarted after adding it.
  • If your Moonraker instance runs on a non-default port, append the port to the URL (e.g. http://192.168.1.100:7125).

API key is invalid

The API key field is not validated by Moonraker — any non-empty string will work. If your slicer rejects the key, ensure the field is not blank.

Upload succeeds but the print does not start

Check whether your slicer's "start print after upload" option is enabled. If it is disabled, the file will be uploaded but you will need to start the print manually from Fluidd.