Chemuxer

/tʃɛˈmʌksər/ — "Che" as in Eclipse Che, "muxer" as in multiplexer.

A web-based terminal multiplexer built with TypeScript, React, and xterm.js. Split panes, tabs, drag-and-drop, command palette, and persistent shell sessions — all in the browser.

Features

• Split panes — drag tabs to edges for VS Code-style splits, resize with draggable separators
• Tabs — per-pane tab bars with drag-and-drop between panes
• Command palette — Cmd+Shift+P / F1 for quick access to all commands
• Session persistence — shell sessions survive browser disconnects; terminal state (including TUI apps) restores on reconnect
• Auto-reconnect — exponential backoff with disconnect banner and countdown
• Layout persistence — split layout survives browser refresh (via localStorage)
• Pane zoom — Cmd+Shift+M to maximize a pane, toggle back to restore layout
• Settings — Monaco-based JSON editor with schema validation, live reload
• Themes — Catppuccin Mocha (dark) and Latte (light), switchable via settings or palette
• Context menu — right-click tabs for rename, close, and split actions

Quick Start

npm install
npm run dev

Open http://localhost:5173 in your browser.

Prerequisites

• Node.js 22+
• A C++ compiler toolchain for node-pty native addon (Xcode CLT on macOS, build-essential on Linux)

Architecture

Single Node.js process: Express serves the React frontend and a WebSocket server manages terminal sessions via node-pty.

graph TB
    subgraph Browser
        A["React + xterm.js"]
    end

    A -- "control WS" --> C
    A -- "I/O WS ×N" --> D

    subgraph Server ["Server · Node.js"]
        B["Express · static files"] -. "serves UI" .-> A
        C["/ws/control"] --> E["SessionManager"]
        D["/ws/:id"] --> F["Session · PTY"]
        E --> F
    end

Loading

• Control WebSocket (/ws/control) — session lifecycle, settings sync, rename events
• I/O WebSockets (/ws/:sessionId) — binary terminal data per session
• Headless xterm.js — server-side virtual terminal for state serialization on reconnect

See Architecture Decision Records for detailed design rationale.

Scripts

Command	Description
npm run dev	Start dev server (backend + Vite frontend)
npm run build	Build for production
npm start	Run production build
npm test	Run all tests
npm run test:watch	Run tests in watch mode

Docker

docker build -t chemuxer .
docker run -p 7681:7681 chemuxer

Configuration

Settings are stored in ./config/settings.json and editable via the built-in Monaco editor (Cmd+Shift+P → Open Settings).

{
  "terminal": {
    "fontFamily": "'JetBrains Mono', monospace",
    "fontSize": 14,
    "theme": "catppuccin-mocha"
  },
  "shell": {
    "path": ""
  },
  "scrollback": {
    "lines": 5000
  }
}

Keyboard Shortcuts

Shortcut	Action
Cmd+Shift+P / F1	Command palette
Cmd+Shift+M	Toggle pane zoom

Tech Stack

• Frontend: React 19, xterm.js 6.x, react-resizable-panels, cmdk, Monaco
• Backend: Node.js, Express 5, ws, node-pty
• Shared: TypeScript end-to-end, shared WebSocket protocol types
• Testing: Vitest (153 tests), Testing Library
• Build: Vite (frontend), tsc (backend)

Contributing

See CONTRIBUTING.md.

License

Eclipse Public License 2.0