muxws

Multiplexed streams over one WebSocket, with HTTP/2 and HTTP/3 stream semantics. muxws carries many independent, cancellable, bidirectional streams on one socket; either end can open a stream. It needs no QUIC or HTTP/3 stack. muxws is defined by its wire format. Python and TypeScript implementations are in this repository; SPEC.md and conformance/ specify the protocol for further implementations.

muxws copies the stream semantics of HTTP/2 and HTTP/3, not their transport. A connection runs over one TCP socket or one Unix domain socket, so all streams share one global message order and there is no per-stream loss recovery. Rationale lists which parts of the HTTP model muxws copies and which it does not; Comparison compares the two protocols frame by frame. muxws does not route requests, serialize domain objects, authenticate peers, store messages durably or define RPC services.

Install

pip install muxws                       # extras: [starlette], [websockets], [msgpack]
npm install muxws                       # optional peers: ws, @msgpack/msgpack

Documentation

The manual is at docs.velis.si/muxws. npm run docs:dev builds and serves it locally.

Status

Alpha. The wire protocol and the packages are versioned independently:

• Wire protocol: generation 1, frozen. The WebSocket subprotocol is muxws.v1.<codec>. The v1 changes only with a breaking wire change.
• Packages: version 0.x. Version 1.0 follows the first confirmed production deployment.

Packages: muxws on PyPI; muxws on npm, with the browser entry point and the muxws/node and muxws/msgpack subpaths.

Licence

MIT. Copyright © 2025 Jure Erznožnik.