WebRTC

In one line

WebRTC lets two browsers (or apps) exchange encrypted audio, video and data directly, peer-to-peer, with no plugins — which is why a video consult can run in a plain browser tab.

The problem it solves

Real-time video used to mean plugins, installs, and proprietary apps — a barrier for patients and clinics alike. WebRTC builds encrypted, plugin-free real-time media right into the browser, so a telehealth visit works from a plain URL on any device. That accessibility is the whole point for population-scale care.

The three pieces

• Signalling — not standardised; you build it (usually a WebSocket server). Peers exchange session descriptions (SDP) to agree on codecs and addresses before any media flows.
• ICE / STUN / TURN — get through NATs and firewalls. STUN discovers a peer's public address; TURN relays the media when a direct path is impossible (the part that costs money at scale).
• Media + data channel — encrypted media (SRTP) and an arbitrary data channel flow peer-to-peer once connected.

For group calls, an SFU (Selective Forwarding Unit) server forwards streams, avoiding an N×N peer mesh.

Where it shows up in digital health

• Browser teleconsultation — including national platforms (eSanjeevani-class).
• Tele-ICU camera feeds and remote procedure proctoring.
• The data channel for live device readings during a video visit.

Platform-side, the build decision is usually "raw WebRTC + your own SFU/TURN" vs a managed media platform — a cost/control trade-off.

Common pitfalls

• Forgetting TURN — without a relay, calls fail behind restrictive networks (hospital firewalls especially); TURN bandwidth is a real cost line.
• DIY signalling security — signalling is yours to build and secure.
• Privacy of recordings — recording a consult is PHI; consent, storage, and DPDP/HIPAA handling apply.

Key takeaways

• WebRTC = plugin-free, encrypted, peer-to-peer audio/video/data in the browser.
• Three parts: signalling (you build it), ICE/STUN/TURN (NAT traversal), media + data channel.
• TURN relays cost money; SFUs enable group calls.
• The engine behind browser telemedicine — accessibility is its core value.