WebTransport

​

Open a session

import { MoqtClient } from "@clutchcall/sdk/moqt";

const client = await MoqtClient.connect(
  "quic://relay.clutchcall.dev",
  workspaceToken,
  (state, reason) => console.log("transport", state, reason ?? ""),
);
// client is live — publish or subscribe voice/<sid>/{uplink,downlink}

from clutchcall.moqt import MoqtClient

client = MoqtClient.connect(
    "quic://relay.clutchcall.dev",
    token=workspace_token,
    on_state=lambda state, reason=None: print("transport", state, reason),
)

• The SDK rewrites the quic:// URL to https:// and attaches the tenant token as a query parameter. The relay’s control plane checks the token before any track flows.
• The client advertises the MoQT version as the WebTransport subprotocol (moqt-16). The relay refuses a session that does not offer it, so this is not optional. The SDK always sends it for you.
• connect returns as soon as the session is up. The client auto-reconnects with capped backoff if the link drops, and it replays every publication and subscription. The onState callback reports Connecting / Connected / Reconnecting / Closed / Failed.

​

How MoQT rides the session

• A control stream — a single bidirectional stream carries MoQT setup and the subscribe/publish signalling. This is where the client and relay agree on versions, announce namespaces, and track subscriptions.
• Object streams — each track group opens its own unidirectional stream of objects. Audio rolls over to a fresh group roughly once a second, so a live call is a rolling series of short-lived streams, each carrying ~1 s of encoded audio objects. Each group on its own stream means a lost or slow group cannot head-of-line-block the next one. The transport keeps moving.

​

Streams vs datagrams

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The server certificate hash

const client = await MoqtClient.connect(
  "quic://127.0.0.1:4443",
  devToken,
  undefined,
  { serverCertificateHash: "Base64Sha256OfTheCert=" },
);

// No hash — the relay's public certificate is trusted normally.
const client = await MoqtClient.connect(
  "quic://relay.clutchcall.dev",
  workspaceToken,
);

​

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