flex:// URL scheme
For Stream Deck, Automator, Terminal, and anything that opens a URL.
open "flex://tally?color=red&animation=blink"
open "flex://text?content=WRAP%20UP&color=white&background=000"
open "flex://clear" Named colors (red, green, amber, blue, white, black) resolve to hex. URL-encoded spaces in content are decoded. No auth required — local URL handler.