KeyOpera is a tiny macOS menubar app that plays mechanical keyboard sounds as you type. It works system-wide on any app, any keyboard, any Mac.
Not at all. KeyOpera is written in Swift and uses Core Audio directly. It sits at around 0% CPU in normal use. You can verify this yourself in Activity Monitor.
Click the menubar icon. One tap toggles sounds on or off. No window to open, no settings to change.
Yes. KeyOpera hooks into the system level, so it works everywhere. Xcode, VS Code, Safari, Terminal, wherever you're typing.
No. The audio engine is optimised for real-time playback. If you notice any delay at all, it's measured in milliseconds and imperceptible in practice.