Inspect WebTransport connections and MoQT protocol traffic right from Chrome DevTools. moqtap adds a new panel to DevTools that gives you full visibility into WebTransport sessions — whether you're debugging a media pipeline or working on MoQT protocol implementations. What it does:

Captures all WebTransport connections on a page, including those created inside Web Workers (essential for WebCodecs and MediaSession workflows)
Auto-detects the MoQT protocol and draft version directly from wire bytes — no configuration needed
Decodes MoQT control messages with full field display, so you can see subscribe requests, track info, and errors as they happen
Tracks active subscriptions with namespace and track name resolution
Shows live bitrate for each session, so you can monitor throughput at a glance
Includes a stream data viewer with hex and JSON modes for inspecting raw payloads
Detects content types automatically — fMP4 video segments, JSON control data, and raw binary
Adds filtering and grouping tools for tracks and streams, including namespace grouping, active-only view, and TX/RX direction filters
Lets you pause stream payload recording without losing control messages or track lifecycle visibility
Captures stack traces for outgoing control messages and unidirectional stream creation, with clickable source links in DevTools
Lets you export and import .moqtrace files to share debug sessions with your team

Works with:

MoQT drafts 07 through 17 (auto-detected)
Plain WebTransport connections (non-MoQT) are displayed gracefully
WebTransport in Web Workers and SharedWorkers
High-throughput video streaming sessions (tested at 40+ Mbps)

Built for developers working with WebTransport and Media over QUIC Transport. Lightweight, non-intrusive, and designed to stay out of your way on sites that don't use WebTransport. Open source: https://github.com/moqtap/extension

moqtap

Published Firefox add-on:

WebTransport Inspector