PeerJS
Simple peer-to-peer with WebRTC
...The server acts only as a connection broker. If you don't want to run your own PeerServer, we offer a free cloud-hosted version of PeerServer. PeerServer is open source and is written in node.js. You can easily run your own. PeerJS simplifies peer-to-peer data, video, and audio calls. Add the PeerJS client library to your webpage. The Peer object is where we create and receive connections. PeerJS uses PeerServer for session metadata and candidate signaling. Every Peer object is assigned a random, unique ID when it's created.