Per-app volume control for the Mac. Part of Domus.
A louver is a set of angled slats over a window opening, letting you adjust how much air and light pass through, Louver does the same for each app's sound. macOS still has one volume for everything; Louver gives every app its own slider and mute, from the menu bar.
Louver uses macOS's Core Audio process taps (no drivers, no kernel extensions): an app you turn down is muted at the audio HAL and its sound is played back at the level you set. Apps at full volume are untouched, their audio passes straight through the system as if Louver weren't running.
This needs the System Audio Recording permission. Nothing is recorded or stored.
./Scripts/dev.sh # rebuild-and-relaunch loop
./Scripts/test.sh # unit tests
./Scripts/bundle.sh # assemble build/Louver.appRequires macOS 26 or later.
MIT, see LICENSE. Bundled third-party software and its licenses are listed in THIRD-PARTY-NOTICES.md.