Single Browser-based App Supporting both RingOut and WebRTC

Yes. RingOut and WebRTC are two different ways to connect voice calls and can both be supported in single web app without authenticating each time. To do this using the RingCentral JavaScript SDK, have the user authorize with the JavaScript SDK and then pass in the JavaScript SDK when instantiating the RingCentral WebRTC WebPhone SDK. An example implementation of this is the RingCentral for Google browser app.