One of the founders of LiveKit here. I've worked on two companies now, fifteen years apart, that needed realtime audio/video infrastructure. Turns out that even in 2021, there aren't many modern, flexible and inexpensive options. I was chatting with my fellow YCS07 batch-mate, @davidz about it, and we explored what it would take to build our own SFU on top of WebRTC. The result is LiveKit.
You can read the more detailed version here, if you're interested: https://blog.livekit.io/and-were-live-kit-5dc7fe03e1bd
We'd love to hear your thoughts and feedback! I'm also curious how other folks' experiences have been with Agora, Twilio, etc.
We'll hang out and chat here in the comments, or if you want to talk live, we hacked up an audio room in our playground (we'll be in there for a few hours, too): https://livekit.io/playground#room=livekit-launch&code=fe54b...
Cheers!