WebTransport Inspector
A Chrome DevTools extension that gives you full visibility into MoQT connections running over WebTransport.
WebTransport Inspector adds a panel to Chrome DevTools that decodes MoQT traffic in real time. No proxies, no extra setup — open DevTools and start inspecting.
Features
Section titled “Features”Connection monitoring
Section titled “Connection monitoring”See every WebTransport connection on the page with live status updates and real-time per-connection bitrate. When you open DevTools mid-session, the extension detects active connections and picks up where you left off. Page reloads cleanly close open sessions.
Control message decoding
Section titled “Control message decoding”All MoQT control messages are decoded and displayed with expand/collapse for message fields. Setup handshakes, subscriptions, publishes, fetches, goaways — every control message is parsed and presented in a readable format.
Stream and object inspector
Section titled “Stream and object inspector”View the full list of QUIC streams with live byte counts. Track individual subscriptions with filtering. See object headers, group/object IDs, priorities, and delivery status.
Payload inspection
Section titled “Payload inspection”The extension auto-detects content types and renders payloads accordingly:
- JSON — interactive JSON viewer with syntax highlighting
- fMP4 — binary view with protocol header highlighting
- Binary — hex viewer with MoQT header fields highlighted in distinct colors
Trace export and import
Section titled “Trace export and import”Export the current session as a .moqtrace file for offline analysis in the moqtap desktop app. Import previously saved traces back into the extension for review. See .moqtrace File Format for format details.
Persistent preferences
Section titled “Persistent preferences”View settings (column widths, expanded sections, filter state) are saved across sessions so you don’t have to reconfigure the panel each time you open DevTools.
Installation
Section titled “Installation”Install from the Chrome Web Store (link coming soon) or load the unpacked extension from source for development.
- Open Chrome DevTools (F12 or Cmd+Opt+I)
- Navigate to the WebTransport Inspector panel
- Load or reload a page that uses WebTransport with MoQT
- Connections appear automatically with live message decoding
The extension works with any WebTransport-based MoQT implementation — it inspects the wire protocol directly, regardless of which client library or relay you’re using.