Mux

A local-only dashboard for running and managing development services. Each service runs under a PTY, with its logs streamed over WebSocket to a React UI. Configure args + env vars per service, switch between named profiles, send input to the running process (e.g. sudo passwords or Quarkus r/q), open the project in VSCode or Terminal, and detect listening ports automatically.

Requirements

• macOS (uses osascript for the folder picker and Terminal.app, open -a for VSCode, lsof + pgrep for port detection)
• Go 1.22+
• Node 20+ and Yarn 1
• VSCode installed (optional — only needed for the Open in VSCode button)

Installing the binary

Download the binary matching your machine (Apple Silicon = arm64, Intel = amd64), then:

chmod +x mux-darwin-arm64
mv mux-darwin-arm64 /usr/local/bin/mux
mux

Open http://localhost:4000 in a browser.

The binary is self-contained: it embeds the React UI and uses ~/.mux/data/ for state. Nothing is written next to the binary.

macOS Gatekeeper

If you downloaded the binary (rather than built it locally), macOS will quarantine it and refuse to run unsigned executables. Either right-click → Open the first time, or remove the quarantine attribute:

xattr -d com.apple.quarantine /usr/local/bin/mux

For wider distribution, sign and notarize the binary with a Developer ID certificate — left out of the v1 scope.

Build

make build

This bundles the React app to web/dist, then compiles a single Go binary named mux that embeds the SPA via go:embed.

To run the production binary:

./mux

The server listens on http://localhost:4000. Override with PORT=4001 ./mux.

Check the version of any binary with ./mux --version.

Dev mode (with hot reload)

In two terminals:

make dev-server      # Go backend on :4000
make dev-web         # Vite frontend on :5173 (proxies /api to :4000)

Open http://localhost:5173.

Data

All persistent state lives under ~/.mux/data/:

• services.json — service definitions, profiles, args, env vars
• shortcuts.json — your customized keyboard shortcuts
• settings.json — your customized settings

Override the location with MUX_HOME=/some/path ./mux.

Features

• Per-service config: name, working directory, command, profile-scoped arguments and environment variables. Auto-save with a 500 ms debounce.
• Named profiles: each service has one or more profiles (e.g. default, clone-db). Switch at any time; only the active profile is applied at start.
• Copy args / env from another service: append (skipping duplicates) or replace.
• PTY-based supervision: spawn under a real PTY so tools that detect a TTY (Quarkus, ANSI colors, sudo prompts) work correctly. Process-group kill on stop (SIGTERM then SIGKILL after 5 s if still alive).
• Live logs: ANSI-colored, zoomable (font size 2–22), clearable per service. Input bar to send keystrokes (mask toggle for passwords).
• Listening ports: backend polls lsof every 3 s, displays detected ports as clickable :port chips that open in a new tab.
• System notifications: browser Notification on transition to crashed and on the first port becoming available after running.
• Import / Export: download services.json (with confirmation) or import another file in merge or replace mode.
• Drag-reorder services in the sidebar; resize the sidebar by its right edge; collapse to a thin strip with ☰.
• Quick-switch services with a searchable palette.

Notes

• HTTP is bound to all interfaces by default; the tool is intended for local use only. Do not expose port 4000 publicly — there is no auth and the API can start arbitrary processes.
• The shortcuts dialog uses physical key codes, so Option-modified keys on macOS (which produce special characters like ß for ⌥S) match by physical key.