cubeb is a cross-platform C library for low-latency audio playback and recording, originally developed by Mozilla for Firefox. It provides a simple callback-based API and supports a wide range of backends including ALSA, PulseAudio, WASAPI, CoreAudio, OpenSL ES, AAudio, JACK, and others. The library handles device enumeration, resampling (via vendored Speex), channel mixing, and real-time streaming. Its architecture uses a vtable pattern ('cubeb_ops') to abstract backend implementations, and includes several high-quality lock-free data structures. While primarily a production library, it includes extensive test suites and debugging tools like audio dumping. The codebase is actively maintained, with ongoing migrations of some backends to Rust, but retains legacy backends (WinMM, OSS) with limited functionality.