WebTransport and MOQ: The Browser Connection

The Browser Gap

One of the biggest challenges for real-time protocols has been browser support. WebRTC solved this with built-in browser APIs, but its peer-to-peer model doesn't scale. Traditional streaming protocols like HLS work in browsers but add seconds of latency.

MOQ bridges this gap through WebTransport.

What is WebTransport?

WebTransport is a web API that provides bidirectional transport over HTTP/3 (which runs on QUIC). It offers:

• Reliable streams: Ordered, reliable byte streams (like TCP)
• Unreliable datagrams: Fire-and-forget messages (like UDP)
• Multiplexing: Many streams over a single connection
• Built-in security: Runs over TLS 1.3

How MOQ Uses WebTransport

MOQ transport maps naturally onto WebTransport's capabilities:

1. Control messages (SUBSCRIBE, ANNOUNCE, etc.) use bidirectional streams
2. Media objects can be sent on unidirectional streams or datagrams
3. Stream multiplexing allows different tracks and priorities on the same connection
4. Session establishment uses the standard WebTransport handshake

// Simplified browser-side MOQ subscription
const transport = new WebTransport("https://relay.example.com/moq");
await transport.ready;

// The MOQ protocol runs over WebTransport streams
const stream = await transport.createBidirectionalStream();
// Send SUBSCRIBE message on the stream...

Browser Support

WebTransport is supported in:

• Chrome/Edge 97+ (stable since January 2022)
• Firefox (behind a flag, with increasing support)
• Safari (under development)

Implications

With WebTransport, any web application can become a MOQ subscriber (or even publisher). This means:

• Live streaming platforms can deliver sub-second latency without custom players
• Real-time collaboration tools can use MOQ for media without WebRTC complexity
• Gaming platforms can stream gameplay with near-zero delay
• Auction and trading platforms can deliver real-time video feeds

The Full Stack

A complete browser-based MOQ stack looks like:

┌─────────────────────┐
│  Web Application    │
├─────────────────────┤
│  MOQ Client (JS)    │
├─────────────────────┤
│  WebTransport API   │
├─────────────────────┤
│  HTTP/3 (QUIC)      │
└─────────────────────┘

This stack is entirely native to the browser — no plugins, extensions, or custom protocols needed.