Sliders

A macOS menu bar app for audio output switching and per-app volume. Switch the output device in one click, connect Bluetooth headphones, set a separate volume for every app, and play audio to several devices at once. Site: sliders.pages.dev.

No telemetry, no kernel extension, no virtual audio driver — the source is open, check for yourself. Requires macOS 15+ on Apple silicon.

Sliders is a fork of Fader by pantafive, extended with a now-playing view for every app and browser tab.

Install

Download the latest dmg. The app updates itself.

Features

• Output switching — headphones, speakers, displays, and AirPlay targets, one click each. Paired Bluetooth headphones connect from the same list.
• Auto-switch — drag rows to rank devices; Sliders follows the best one present.
• Several outputs at once — drag a device onto the Output section and both play together, each with its own slider.
• Per-app volume — a slider and mute for every app that plays sound; levels persist. Apps at full volume play untouched, bit-perfect.
• Per-app output — drag one or more devices onto an app to play it through exactly those outputs, each with its own volume; everything else stays on your main output.
• Now playing — every track, video, and browser tab that's playing shows under its app with artwork, play/pause, and scrubbing. Control Center shows one; Sliders shows all of them.
• Microphone — switch the default input, set gain, and see which apps are listening.
• In sync — system volume follows the volume keys and Control Center; scrolling over any slider adjusts it.

Permissions

• System Audio Recording, for per-app volume: macOS gates audio taps behind it, and Sliders asks the first time you move an app's slider. The tapped audio never leaves the Mac.
• Automation, for now playing: macOS asks once per app. For a browser, that happens the first time the popover is open while it plays; Sliders then lists its tabs and runs a small script in them that reads and controls the page's media. For Spotify, Music, and TV, it happens on the first play/pause or scrub that macOS can't route on its own. Listing each tab separately also needs "Allow JavaScript from Apple Events" turned on in the browser; Sliders shows where when it's needed.

Artwork for a browser tab loads from the image address the page itself provides, the same one the browser would show.

Development

Swift 6, strict concurrency. The Xcode project is generated from project.yml — edit that, not the .xcodeproj. make drives local work: gen, build, test, lint, run, clean. Pushing a v* tag builds, signs, notarizes, and publishes a release.

Contributing

Bug reports and pull requests are welcome; for anything bigger than a fix, open an issue first. make test and make lint must pass; commits follow Conventional Commits. The real-time audio callback allows no allocation, locks, Objective-C, or logging — changes there get extra scrutiny. Anything that phones home will be declined.

Security

Report security issues privately via GitHub security advisories, not public issues.

License

MIT. Sliders keeps Fader's original copyright notice alongside its own.