[saljam]

The website uses Google's.

On command line it's an option and Google's is default. I'd like to make the signalling server also a STUN server at some point.

[crazygringo]

Oh that's interesting... I had no idea there were publicly available STUN servers like that.

But way back in 2014 a Google employee does seem to have confirmed it's free to use, but comes without guarantees.

[1] https://groups.google.com/d/msg/discuss-webrtc/shcPIaPxwo8/F...