I'm the creator of Peer Calls [1], a peer to peer video conferencing web app using WebRTC, and it has a basic chat functionality (sending files is a little quirky). The first release was back it in 2016. Users create a room and share the link.
It's built in NodeJS/React/TypeScript, and I just recently ported the backend to Go because I wanted to build a Selective Forwarding Unit using pion/webrtc. You can test this in the alpha release on peercalls.com/alpha [2].
Would love to get more feedback and/or bug reports! Open source, available on GitHub [3].