Felipe,
Your question is about the Webrtc "client" or the server that will be responsible for Signaling (message exchange)?
If it is server related, there are several Websocket projects in PHP, such as:
At the Webrtc (Client/Server) connection points you will use Websocket to signal and send messages that negotiate the connection between the points, after which these points will connect directly to each other (or through a TURN server).
On the website Webrtc has a lot of material and content to help you with the task.
PS.
Just out of curiosity, could you explain to me why I can’t use the Node server?
You could specify the Node server information needed to start the connection you mentioned?
– KveRa