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rmux multiplexing

All Hiddify features

rmux is one more protocol for sing-box multiplexing: "multiplex": {"protocol": "rmux"} on an outbound. Like smux, yamux and h2mux, it carries many connections inside one connection to the server. It comes from sing-box-extended (github.com/shtorm-7/rmux).

Why use it

  • Fewer connections to the server: each new connection opens a stream in a session that already exists, with no new handshake, so it starts faster and shows fewer connections to the network.
  • You want a multiplexer other than the usual ones; rmux is newer and less common on the wire.

How it gets past filtering

It does not on its own. It runs inside the outbound's protocol and transport, which are what the network sees.

How it works

  • Data travels in frames of at most 32 KiB, each tagged with its stream.
  • A stream can be closed for writing while it still reads, as with h2mux.
  • Sessions are kept and reused as for the other protocols; keepalive frames are off, as sing-box manages idle sessions itself.

Configuration

{
  "type": "vless",
  "server": "example.com",
  "server_port": 443,
  "uuid": "b831381d-6324-4d53-ad4f-8cda48b30811",
  "multiplex": { "enabled": true, "protocol": "rmux", "max_connections": 4 }
}

The server's inbound needs "multiplex": {"enabled": true} and Hiddify's sing-box: it accepts rmux like the other protocols, and an upstream sing-box server refuses it. The other multiplex fields work as for the other protocols. No build tag is needed.

See also

Last update: February 26, 2026

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