FWIW, on macOS, this places a phone call... $ open facetime-audio:6175007369 That URL scheme can also be used on iOS. [CLARIFICATION EDIT: this places a Face

FWIW, on macOS, this places a phone call... $ open facetime-audio:6175007369 That URL scheme can also be used on iOS. [CLARIFICATION EDIT: this places a FaceTime Audio call. The number you're calling would need to be a contact who can accept that call. Not exactly general-purpose.]