WebTransport Application Protocol Negotiation

concepts

1. WebTransport ALPN

   Pick client and server protocol lists, watch the negotiation pick a winner, see the wire-shape request — then attempt a real new WebTransport(url, {protocols}) against a URL you choose.

2. Sub-protocol router

   The router pattern: one endpoint, multiple sub-protocols (game-v3, chat-v1, telemetry). Pick the offered + supported sets, see which the negotiation picks and which handler runs.

3. Protocol negotiator sim

   Type your client offer list and server's supported set. Watch the negotiation pick a winner, see the exact HTTP headers Chrome would send and the server's response, then attempt a real new WebTransport(url, { protocols }) against any URL.

4. ALPN Benchmark

   Drag-and-drop protocol candidate list with a server preference selector. An ALPN simulation shows step-by-step match/skip per candidate. A latency comparison bar chart covers 1–5 candidates with adjustable base RTT, and a real new WebTransport(url, { protocols: [...] }) test attempts the connection. A fallback chain visualizer covers four server configurations.

why it shipped

WebTransport Application Protocol Negotiation allows negotiation of the protocol used by the web application within the WebTransport handshake. A web application can specify a list of application protocols offered when constructing a WebTransport object, which are then conveyed to the server via HTTP headers; if the server picks one of those protocols, it

references

• ChromeStatus entry
• Spec