Debug MoQT Sessions

You're building on Media over QUIC Transport but you can't see what's happening on the wire. Messages are binary-encoded, state is distributed across streams, and errors are opaque. moqtap gives you the visibility you need.

The problem

MoQT is a binary protocol running over QUIC. You can't read messages in a browser's network tab. You can't curl a MoQT relay. When your subscriber isn't getting objects, you don't know if the publisher stopped sending, the relay dropped the subscription, or the QUIC connection degraded. You need a tool that understands the protocol.

How to debug with moqtap

1

Connect to your relay

Enter the relay URL — native QUIC (moqt://) or WebTransport (https://). Select the MoQT draft version. Accept self-signed certs for local development or use system trust for production.

2

See every control message

The control stream log shows every message in real-time: SUBSCRIBE, PUBLISH, FETCH, GOAWAY, and more. Each message is parsed with human-readable fields, timestamps, and direction. Filter by type or search for specific values.

3

Subscribe to tracks and fetch data

Subscribe with any filter type to see objects arrive live. Use FETCH to retrieve historical objects. Discover available namespaces before subscribing.

4

Inspect objects and payloads

Objects are auto-detected as text, JSON (with syntax highlighting), or binary (with hex viewer and ASCII sidebar). See the content your subscribers will receive.

5

Check transport health

Real-time QUIC stats show RTT, packet loss, congestion window, bytes transferred, and stream counts. Correlate application-level issues with transport-level behavior.

6

Export and share

Record the full session as a .moqtrace file. Share it with your team, attach it to a bug report, or import it later for offline analysis.

Choose your tool

moqtap Desktop

Free

Full-featured native app with QUIC and WebTransport support. Connect, inspect, subscribe, fetch, and export traces.

WebTransport Inspector

Free

Chrome DevTools extension for WebTransport-based MoQT. Debug without leaving the browser.

moqtap Desktop Pro

$29/mo

Proxy mode, multi-session correlation, and advanced latency analytics for professional MoQT development.

Frequently asked questions

How do I debug MoQT sessions?
Use moqtap Desktop or the WebTransport Inspector browser extension to connect to a MoQT relay. Both tools decode control messages, let you subscribe to tracks, fetch data, and inspect object payloads — giving you full visibility into what's happening on the wire.
Can I debug MoQT in the browser?
Yes. The free WebTransport Inspector Chrome extension adds a MoQT panel to Chrome DevTools. It intercepts WebTransport connections and decodes MoQT messages in real-time. For native QUIC connections, use moqtap Desktop.
What is a .moqtrace file?
A .moqtrace file is a CBOR-encoded recording of a complete MoQT session. It captures timestamps, message direction, parsed fields, raw bytes, and QUIC stats. You can export traces from moqtap and share them with your team for collaborative debugging.
Is moqtap like Wireshark for MoQT?
Similar concept, but purpose-built for MoQT. Where Wireshark shows you raw packets, moqtap understands the MoQT protocol — it parses control messages, tracks subscriptions, decodes objects, and shows you QUIC transport stats. You see protocol semantics, not just bytes.
Does moqtap support multiple MoQT draft versions?
Yes. moqtap supports multiple IETF MoQT draft versions. You can select the draft when connecting, making it useful for testing implementations across different protocol revisions.

Start debugging MoQT today

Free and cross-platform. See inside the protocol in minutes.

Download moqtap