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Audio sound (OSC 440)

Category: extensions · Baseline: legacy · Tags: Operating System Commands (OSC) · Specification ↗

ESC ] 440 ; wavfile BEL
OSC 440 plays a WAV audio file as terminal output. The sequence is ESC ] 440 ; wavfile BEL where wavfile is a path or identifier for an audio sample. This is a mintty-only extension and one of the most unusual terminal features in the wild — no other terminal emulator exposes general-purpose audio playback through an escape sequence. mintty originally added this for accessibility and notification scripting on Windows, where Cygwin/MSYS shell scripts could trigger arbitrary sound effects without a separate player. Other terminals silently consume the sequence; audio playback happens nowhere except mintty.
How this is testedpartial
Send OSC 440 ; bell.wav BEL and verify the terminal consumes the sequence (cursor position unchanged).

The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.

Analysis2026-04-06

Supported by all 4 tested terminals — universal adoption. Part of the Unicode baseline.

Supported by 6 of 14 backends (43%)

Terminal Applications

TerminalVersionSupportNotes
iTerm23.6.9✓ yes
Ghostty1.3.1✓ yes
Terminal.app2.15✓ yes
Kitty0.46.2✓ yes
VS Code1.113.0? unknown
Warp0.2026.03.18.08.24.03? unknown
Cursor2.6.21? unknown

Headless Backends

Parser correctness only — a means the parser accepts the sequence.

BackendVersionSupportNotes
Alacritty0.26.0? unknown
vt100.js0.2.1? unknown
vterm0.2.0? unknown
WezTerm0.1.0-fork.5? unknown
xterm.js5.5.0? unknown