WebRTC
Also written as Web Real-Time Communication, LiveKit, Agora SDK
The technology built into browsers and phones for live audio, video and data between users. It powers video calls, telehealth consultations, live tutoring and voice AI agents. Making it reliable over poor networks and corporate firewalls needs extra relay and media servers; companies such as LiveKit and Agora sell that infrastructure.
Think of it like
A direct phone line between two people, plus a switchboard for when they can't reach each other directly.
Junior or senior?
Hard to do well at scale, so differentiating.
Senior sounds like
Talks about call quality on bad networks, firewalls, recording, and scaling to group calls with a media server.
Ask them
“What did you do to keep call quality acceptable when users had poor connections?”