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Real-time & Media

Streaming, bidirectional communication, and media delivery: WebSocket, WebTransport, SSE, WebRTC, MSE/EME.

Real-timeWebRTCMedia Delivery
1
Must Know
5
Should Know
4
Niche

Must Know

1 spec
RFC 6455RFCMust Know

WebSocket

Real-time features — chat, live dashboards, collaborative editing, notifications, trading UIs — run on WebSockets. Every serious app eventually needs them.

ProductReal-time
Details

Should Know

5 specs
HTML LS §SSEWHATWGShould Know

SSE

The go-to protocol for server-push without WebSocket complexity. Used for AI/LLM streaming responses, live notifications, and real-time dashboards over plain HTTP.

ProductReal-time
Details
W3C WebRTCW3CShould Know

WebRTC

Video calls (Meet, Zoom web), voice calls, peer-to-peer file transfer, and collaborative tools. The browser API surface for real-time A/V communication.

ProductWebRTC
Details
RFC 8445RFCShould Know

ICE

NAT traversal is why WebRTC calls fail. ICE is how browsers find a working path between peers. Know it when debugging call connectivity failures.

ProductWebRTC
Details
RFC 8489RFCShould Know

STUN

STUN is how WebRTC discovers the public-facing address for peer-to-peer connections. Every WebRTC deployment needs a STUN server.

ProductWebRTC
Details
RFC 8656RFCShould Know

TURN

~15-20% of WebRTC calls require TURN relay because both peers are behind symmetric NAT. Without TURN, those calls fail silently.

ProductWebRTC
Details

Niche / Specialized

4 specs
W3C WebTransportW3CNiche

WebTransport

For gaming, live collaboration, and real-time data where WebSocket's TCP head-of-line blocking matters. Runs over QUIC so multiple streams don't block each other.

ProductReal-time
Details
RFC 5764RFCNiche

DTLS-SRTP

WebRTC media is always encrypted. DTLS-SRTP is the protocol that does it. Know it when troubleshooting media security negotiation or DTLS handshake failures.

ProductWebRTC
Details
W3C MSEW3CNiche

MSE

Video players (YouTube, Netflix, Twitch) use MSE for adaptive streaming. Required if you build a custom media player or do in-browser video processing.

ProductMedia Delivery
Details
W3C EMEW3CNiche

EME

Required for any platform that distributes premium or licensed video content (streaming services, pay-per-view, licensed media).

ProductMedia Delivery
Details