Protocol Support

Protocol Feature Support

A feature-by-feature snapshot of what Titanium Web Proxy actually implements for HTTP/1.0, HTTP/1.1, and HTTP/2, so you can tell at a glance whether something you depend on is fully supported, relayed best-effort, or not implemented yet. "Yes" means the proxy actively parses/enforces the feature (and you can observe/modify it via the public API where relevant); "Partial" means it works for the common case but has a known gap; "No" means it isn't implemented.

This table reflects the develop branch as of the HTTP/1.x and HTTP/2 gap-closure work (chunked trailers, interim 1xx responses, and TLS body-write-hook parity for HTTP/1.x; HPACK dynamic-table correctness/reuse, HEADERS/CONTINUATION reassembly and re-splitting, trailers, interim 1xx responses, two-hop flow control, SETTINGS/PING/GOAWAY handling, and synthetic-response API parity for HTTP/2). HTTP/2 has gone through a full regression pass and is now on by default (ProxyServer.EnableHttp2 = true); set it to false to force HTTP/1.1 only. If you find something inaccurate, please open an issue.

Connections and framing

Feature	HTTP/1.0	HTTP/1.1	HTTP/2	Notes
Persistent connections / keep-alive	Yes	Yes	Yes (inherent)	Connection: keep-alive (1.0) / default (1.1); HTTP/2 multiplexes over one connection.
Chunked transfer-encoding	N/A (no chunked in 1.0)	Yes	N/A (HTTP/2 uses DATA frames, not chunking)	Read and write, both request and response, via HttpStream.
Chunked trailers (trailing headers)	N/A	Yes	Yes	See RequestResponseBase.TrailingHeaders; forwarded/emitted for HTTP/1.x. For HTTP/2, a second HEADERS block without request/status pseudo-headers is decoded as trailers and re-encoded/relayed without re-firing BeforeRequest/BeforeResponse.
Expect: 100-continue	Yes	Yes	N/A (no equivalent frame flow)	ProxyServer.Enable100ContinueBehaviour.
Other 1xx interim responses (e.g. 103 Early Hints)	N/A	Yes	Yes	Relayed to the client (looping past on the HTTP/1.x server connection, or on their own HEADERS frame for HTTP/2) without invoking BeforeResponse/locking the final Response; not yet exposed as a dedicated event.
HEADERS/CONTINUATION reassembly and re-splitting	N/A	N/A	Yes	Multi-frame inbound header blocks are reassembled before HPACK decoding; outbound blocks larger than the peer's SETTINGS_MAX_FRAME_SIZE are split back across HEADERS + CONTINUATION.
Upgrade / WebSocket (101 Switching Protocols)	N/A	Yes	N/A	Raw duplex relay once upgraded; see RequestHandler.HandleWebSocketUpgrade.
CONNECT tunneling	Yes	Yes	Yes (via ExplicitProxyEndPoint)	Supports both decrypt-and-inspect and pass-through-as-opaque-tunnel.
Stream multiplexing	N/A	N/A	Yes	Concurrent streams tracked per connection in Http2Helper; a slow synthetic response on one stream no longer blocks frames for other streams.
HPACK header compression	N/A	N/A	Yes	Both decode and encode reuse a persistent, connection-direction-scoped dynamic table, so repeated headers are indexed/re-indexed correctly on both sides.
Flow control (WINDOW_UPDATE)	N/A	N/A	Yes	Independent send-side window accounting per connection and per stream on each of the two TLS legs (client↔proxy, proxy↔server); validates length/increment/overflow and translates rather than blindly relays.
Server push (PUSH_PROMISE)	N/A	N/A	No	Not decoded/transcoded; no public API to originate a push (push is deprecated in browsers, so low priority).
PING / keepalive frames	N/A	N/A	Yes	ACKed locally by the proxy on each leg; not blindly relayed.
SETTINGS negotiation	N/A	N/A	Yes	HEADER_TABLE_SIZE, MAX_FRAME_SIZE, and INITIAL_WINDOW_SIZE are validated (range-checked, malformed values rejected) and applied per leg; the proxy sends its own SETTINGS on each leg rather than relaying the peer's verbatim.
RST_STREAM / per-stream cancellation	N/A	N/A	Yes	Cleans up the corresponding session/flow-control state and relays the error code.
GOAWAY / connection shutdown	N/A	N/A	Yes	Parses lastStreamId/error code, stops admitting new streams above it, cancels in-flight work that can't complete, and relays to the other leg.

Body handling and streaming

Feature	HTTP/1.0	HTTP/1.1	HTTP/2	Notes
Buffered body read/modify (GetRequestBody/SetResponseBodyString, etc.)	Yes	Yes	Yes
Per-chunk streaming hooks (OnRequestBodyWrite/OnResponseBodyWrite) - plain HTTP	Yes	Yes	Yes
Per-chunk streaming hooks - TLS-decrypted connections	Yes	Yes	Yes	Fixed for HTTP/1.x: the hook now fires with parity for SslStream-backed connections, not just plain NetworkStream.
Synthetic streamed responses (RespondStreaming)	Yes	Yes	Yes	Chunked or fixed-length framing chosen automatically from the response headers you set.
Automatic decompression for body inspection (gzip/deflate/brotli)	Yes	Yes	Yes
Multipart/form-data boundary-aware streaming	Yes	Yes	N/A (not multipart-aware over h2 yet)

Interception APIs

Feature	HTTP/1.0	HTTP/1.1	HTTP/2	Notes
Header/body modification in BeforeRequest/BeforeResponse	Yes	Yes	Yes	Every HEADERS block is fully decoded/transcoded, so mutations made in the event handler are re-encoded and relayed rather than passed through opaquely.
Synthetic responses (Ok, Respond, Redirect, GenericResponse) from BeforeRequest	Yes	Yes	Yes	The request is never forwarded upstream; any unfinished client request body already in flight is drained with flow-control credit returned.
Respond replacing an already-received response from BeforeResponse	Yes	Yes	Yes	The origin's own response body, if still arriving, is discarded (with flow-control credit still returned) in favor of the replacement.
RespondStreaming (synthetic streamed body)	Yes	Yes	Yes	See "Synthetic streamed responses" above for framing details.

Proxying, auth, and misc

Feature	Support	Notes
Explicit, transparent, and SOCKS4/5 endpoints	Yes	ExplicitProxyEndPoint, TransparentProxyEndPoint, SocksProxyEndPoint.
Upstream proxy chaining (HTTP/HTTPS/SOCKS)	Yes	Static, per-request (GetCustomUpStreamProxyFunc), or system-gateway detection.
Proxy Basic authentication	Yes	ProxyBasicAuthenticateFunc.
Windows authentication (Kerberos/NTLM) to upstream servers	Yes	EnableWinAuth.
Mutual TLS to upstream servers	Yes	ClientCertificateSelectionCallback / ServerCertificateValidationCallback.
Upstream connection pooling	Yes	EnableConnectionPool (default on).

Where to look for more detail

• Streaming Bodies - the OnRequestBodyWrite/OnResponseBodyWrite/RespondStreaming APIs in depth.
• Home - general usage and the rest of the public API surface.