How do I toggle Dark Mode or the app menu using a URL or command line?

Use the toggle operation with the feature name as a parameter. Command-line parameters need a leading hyphen. In a URL, put the parameters after the question mark.

Enable the integration method you intend to use in Settings > Application > Integration. BetterDisplay must be running and ready to handle the request. Toggling macOS Dark Mode requires Pro. Showing the app menu does not independently require Pro.

For a launcher that accepts a URL, use either of these raw URLs:

BetterDisplay://toggle?darkMode
BetterDisplay://toggle?appMenu

No display selector is needed because these are app-wide features. If you configured an integration token, include its URL-encoded value as an additional token parameter.

In a shell, quote the URL so the question mark is passed literally:

open 'BetterDisplay://toggle?darkMode'
open 'BetterDisplay://toggle?appMenu'

For direct command-line access to the app installed in Applications, use:

/Applications/BetterDisplay.app/Contents/MacOS/BetterDisplay toggle -darkMode
/Applications/BetterDisplay.app/Contents/MacOS/BetterDisplay toggle -appMenu

darkMode without the leading hyphen is not a command-line parameter. If you need a known final state, use set -darkMode=on or set -appMenu=on instead of toggling. Use off for the opposite state. See the integration syntax reference for access settings, tokens and other operations.