Bela is an open-source embedded platform for ultra-low-latency audio and sensor processing based on the BeagleBone Black single-board computer. It features stereo audio I/O, 8 each of 16-bit DC-coupled analog I/O, 16 digital I/O, all sampled at audio rates. Bela features a unique hard-real-time audio processing environment capable of latency under 1ms. It has a convenient browser-based IDE with in-browser oscilloscope, and features support for C/C++, Pd, SuperCollider, FAUST and other languages.