There are native libraries available for both iOS and Android. I didn't want end-user to install any. Just to click the invitation link and start chatting.
I am developing a video chat + screen share for a school. I am looking for similar browser based application "Click to Start" without installing an app or downloading anything.
I use {reactJS,socket.io,simple-peer,nodeJS}. you can skip the reactjs. There are a lot of tutorials available for video chat apps using webrtc+socket.io. https://appr.tc/ is open-sourced but not actively maintained.