Protocol support
Feature snapshot for HTTP/1.0, HTTP/1.1, HTTP/2, and HTTP/3. HTTP/2 is on by default (ProxyServer.EnableHttp2 = true). HTTP/3 is experimental (TWP001) and opt-in (EnableHttp3 = true).
Protocol bridges
| Client | Origin | Kind |
|---|---|---|
| HTTP/1.x | HTTP/1.x | Native |
| HTTP/2 | HTTP/2 | Native (ALPN MITM; prior-knowledge h2c on transparent reverse) |
| HTTP/3 | HTTP/3 | Native when EnableHttp3 |
| HTTP/1.1 ↔ HTTP/2 | Bridge | When UpstreamHttpProtocol + AllowHttpProtocolTranslation |
| HTTP/1.1 / HTTP/2 ↔ HTTP/3 | Bridge | When H3 selected |
| HTTP/3 → HTTP/2 / HTTP/1.1 | Bridge | Via origin connection helpers |
Not supported: Upgrade: h2c (prior-knowledge only); mid-connection H2→H3 on an open H2↔H2 MITM session; WebSocket over HTTP/3; explicit QUIC proxying (inbound H3 is transparent QUIC / dual-listen only).
Connections and framing (high level)
| Feature | H1.0 | H1.1 | H2 | H3 |
|---|---|---|---|---|
| Keep-alive / multiplexing | Yes | Yes | Yes | Yes |
| Chunked / DATA frames | N/A / Yes | Yes | DATA | DATA |
| Trailers | N/A | Yes | Yes | Yes |
| WebSocket | Yes | Yes | RFC 8441 | No |
For the full matrix (headers, flow control, SETTINGS/PING/GOAWAY, streaming, auth), see the Protocol-Support wiki.