  We describe Howl, an open-source wake word detection toolkit with native
support for open speech datasets, like Mozilla Common Voice and Google Speech
Commands. We report benchmark results on Speech Commands and our own freely
available wake word detection dataset, built from MCV. We operationalize our
system for Firefox Voice, a plugin enabling speech interactivity for the
Firefox web browser. Howl represents, to the best of our knowledge, the first
fully productionized yet open-source wake word detection toolkit with a web
browser deployment target. Our codebase is at
https://github.com/castorini/howl.
