I've been trying out Snips, it's pretty cool and works reasonably well. A lot of the overall system is open source and runs offline, but the training happens on

I've been trying out Snips, it's pretty cool and works reasonably well. A lot of the overall system is open source and runs offline, but the training happens on their servers and is closed source AFAIK. You download the trained model and can run it on a raspberry pi etc offline. But they claim that what Snips offers for free isn't nearly as good as what the commercial offering does. My priorities unfortunately shifted away from finding out about the quality difference. IIRC Snips's business model is to create custom voice agents that run offline for other companies and services around that, eg. custom hotwords etc.