1. Socket programming using web socket/socket.io. 2. Developing custom signaling server using socket.io for voice/video calling with Google stun/turn video service (for free, no charge). - Developing signaling server into custom backend. - Establishing channel for p2p mesh with sdp and offers via signaling server. - Establishing interactive connectivity(as ICE server) - Using freely webRTC.org libraries in web app and mobile app.