Why do we need a server at all?

[Tomas-M]

May I kindly ask you for an explanation, why do we need peer server at all? I don't get it. WebRTC works without it at all, so why peer.js library needs a broker? Would you please provide some technical details whats happening under the hood on the server? Just briefly. Thank you.

[Kaideane]

The "broker" here is essentially the signalling server used to set up WebRTC peer to peer connections.
Your concept of "WebRTC works without it at all", may not be complete. Signalling was intentionally left out of the WebRTC stack, this opens the door for a lot of creativity and interoperability for WebRTC based applications.