AudioTee.js: macOS System Audio Capture for Node.js

AudioTee.js brings system-wide audio capture to Node.js developers on macOS by wrapping a bundled Swift binary built with Core Audio taps. The library streams system audio as PCM‑encoded chunks via an EventEmitter interface, making it easier to pipe live audio into tools like speech recognition services.

It offers a familiar API pattern: developers can configure sample rate, chunk duration, optional process filters, and muting of the output audio. The underlying binary remains lightweight (under 600 KB), cross-platform across Intel and Apple silicon Macs, and emits fixed‑size audio buffers according to event timing parameters.

The article also outlines current limitations—AudioTee.js requires macOS 14.2 or later, captures only from the default output device, and outputs in mono PCM. Despite these constraints, the author views this as a long-awaited, native way to access system audio, inviting early adopters to try the beta version and contribute feedback or feature requests.