How is TheOnline Town made?

Hey IndieDevs,

Wondering if you guys have checked theonline.town , it is a top down game + video chat that opens up your cam+audio feed if you get close to the other players.

I was invited to one of the rooms and it was just awesome! Got me thinking of possibilities but have no clue to how hack this thing together.

If any one of you have any experience with webrtc, js game engine that can tie in the whole thing together?

Curious to hear your thoughts and ideas, Thanks!

PS: Check it out here, theonline.town