Features
- Browser import — Import cookies, history, and sessions from Chrome, Firefox, Arc, and 20+ browsers so browser panes start authenticated
- Custom commands — Define project-specific actions in
cmux.json that launch from the command palette
- Scriptable — CLI and socket API to create workspaces, split panes, send keystrokes, and automate the browser
- Native macOS app — Built with Swift and AppKit, not Electron. Fast startup, low memory.
- Ghostty compatible — Reads your existing
~/.config/ghostty/config for themes, fonts, and colors
- GPU-accelerated — Powered by libghostty for smooth rendering
Install
DMG (recommended)
Open the .dmg and drag cmux to your Applications folder. cmux auto-updates via Sparkle, so you only need to download once.
Homebrew
brew tap manaflow-ai/cmux
brew install --cask cmux
To update later:
brew upgrade --cask cmux
On first launch, macOS may ask you to confirm opening an app from an identified developer. Click Open to proceed.
Why cmux?
I run a lot of Claude Code and Codex sessions in parallel. I was using Ghostty with a bunch of split panes, and relying on native macOS notifications to know when an agent needed me. But Claude Code's notification body is always just "Claude is waiting for your input" with no context, and with enough tabs open I couldn't even read the titles anymore.
I tried a few coding orchestrators but most of them were Electron/Tauri apps and the performance bugged me. I also just prefer the terminal since GUI orchestrators lock you into their workflow. So I built cmux as a native macOS app in Swift/AppKit. It uses libghostty for terminal rendering and reads your existing Ghostty config for themes, fonts, and colors.
The main additions are the sidebar and notification system. The sidebar has vertical tabs that show git branch, linked PR status/number, working directory, listening ports, and the latest notification text for each workspace. The notification system picks up terminal sequences (OSC 9/99/777) and has a CLI (cmux notify) you can wire into agent hooks for Claude Code, OpenCode, etc. When an agent is waiting, its pane gets a blue ring and the tab lights up in the sidebar, so I can tell which one needs me across splits and tabs. Cmd+Shift+U jumps to the most recent unread.
The in-app browser has a scriptable API ported from agent-browser. Agents can snapshot the accessibility tree, get element refs, click, fill forms, and evaluate JS. You can split a browser pane next to your terminal and have Claude Code interact with your dev server directly.
Everything is scriptable through the CLI and socket API — create workspaces/tabs, split panes, send keystrokes, open URLs in the browser.
The Zen of cmux
cmux is not prescriptive about how developers hold their tools. It's a terminal and browser with a CLI, and the rest is up to you.
cmux is a primitive, not a solution. It gives you a terminal, a browser, notifications, workspaces, splits, tabs, and a CLI to control all of it. cmux doesn't force you into an opinionated way to use coding agents. What you build with the primitives is yours.
The best developers have always built their own tools. Nobody has figured out the best way to work with agents yet, and the teams building closed products definitely haven't either. The developers closest to their own codebases will figure it out first.
Give a million developers composable primitives and they'll collectively find the most efficient workflows faster than any product team could design top-down.
Documentation
For more info on how to configure cmux, head over to our docs.
Keyboard Shortcuts
Workspaces
| Shortcut | Action |
|---|
| ⌘ N | New workspace |
| ⌘ 1–8 | Jump to workspace 1–8 |
| ⌘ 9 | Jump to last workspace |
| ⌃ ⌘ ] | Next workspace |
| ⌃ ⌘ [ | Previous workspace |
| ⌘ ⇧ W | Close workspace |
| ⌘ ⇧ R | Rename workspace |
| ⌥ ⌘ E | Edit workspace description |
| ⌘ B | Toggle sidebar |
| ⌥ ⌘ B | Toggle right sidebar |
| ⌘ ⇧ E | Toggle right sidebar focus |
Surfaces
| Shortcut | Action |
|---|
| ⌘ T | New surface |
| ⌘ ⇧ ] | Next surface |
| ⌘ ⇧ [ | Previous surface |
| ⌃ Tab | Next surface |
| ⌃ ⇧ Tab | Previous surface |
| ⌃ 1–8 | Jump to surface 1–8 |
| ⌃ 9 | Jump to last surface |
| ⌘ W | Close surface |
Split Panes
| Shortcut | Action |
|---|
| ⌘ D | Split right |
| ⌘ ⇧ D | Split down |
| ⌥ ⌘ ← → ↑ ↓ | Focus pane directionally |
| ⌘ ⇧ H | Flash focused panel |
Browser
Browser developer-tool shortcuts follow Safari defaults and are customizable in Settings → Keyboard Shortcuts.
Command palette navigation shortcuts, including ⌃ P, are also customizable and can be cleared so the keypress reaches the active terminal.
| Shortcut | Action |
|---|
| ⌘ ⇧ L | Open browser in split |
| ⌘ L | Focus address bar |
| ⌘ [ | Back |
| ⌘ ] | Forward |
| ⌘ R | Reload page |
| ⌥ ⌘ I | Toggle Developer Tools (Safari default) |
| ⌥ ⌘ C | Show JavaScript Console (Safari default) |
Notifications
| Shortcut | Action |
|---|
| ⌘ I | Show notifications panel |
| ⌘ ⇧ U | Jump to latest unread |
| ⌥ ⌘ U | Toggle current item unread state |
| ⌃ ⌘ U | Mark current item as oldest unread and jump to next latest unread |
Find
| Shortcut | Action |
|---|
| ⌘ F | Find |
| ⌘ ⇧ F | Find in directory |
| ⌘ G / ⌥ ⌘ G | Find next / previous |
| ⌥ ⌘ ⇧ F | Hide find bar |
| ⌘ E | Use selection for find |
Terminal
| Shortcut | Action |
|---|
| ⌘ K | Clear scrollback |
| ⌘ C | Copy (with selection) |
| ⌘ V | Paste |
| ⌘ + / ⌘ - | Increase / decrease font size |
| ⌘ 0 | Reset font size |
Window
| Shortcut | Action |
|---|
| ⌘ ⇧ N | New window |
| ⌘ ⇧ O | Reopen previous session |
| ⌘ , | Settings |
| ⌘ ⇧ , | Reload configuration |
| ⌘ Q | Quit |
Nightly Builds
Download cmux NIGHTLY
cmux NIGHTLY is a separate app with its own bundle ID, so it runs alongside the stable version. Built automatically from the latest main commit and auto-updates via its own Sparkle feed.
Report nightly bugs on GitHub Issues or in #nightly-bugs on Discord.
Session restore
Quitting cmux saves the current session. On relaunch, cmux restores app-owned
state:
- Window/workspace/pane layout
- Working directories
- Terminal scrollback (best effort)
- Browser URL and navigation history
cmux does not checkpoint arbitrary live process state. tmux, vim, shells, and
unsupported terminal apps reopen as normal terminals.
Supported agent sessions can resume when hooks have saved a native session ID.
Install hooks after installing the agent CLI so its binary is on PATH:
cmux hooks setup
cmux hooks setup codex
cmux hooks setup --agent opencode
cmux hooks setup installs supported agents it can find and prints a summary
for skipped agents. Supported resume integrations include Claude Code, Codex,
OpenCode, Pi, Amp, Cursor CLI, Gemini, Rovo Dev, Copilot, CodeBuddy, Factory,
and Qoder. Claude Code is handled by the cmux Claude wrapper when Claude
integration is enabled in Settings.
To keep restored agent terminals idle instead of automatically running their resume commands,
turn off Settings > Terminal > Resume Agent Sessions on Reopen or set this in
~/.config/cmux/cmux.json:
{
"terminal": {
"autoResumeAgentSessions": false
}
}
This only disables automatic agent resume commands. cmux still restores the saved layout,
working directories, scrollback, and browser history.
If you need to reapply the last saved snapshot manually, use:
File > Reopen Previous Session⌘ ⇧ Ocmux restore-session
Under the hood, cmux writes a versioned snapshot under
~/Library/Application Support/cmux/ and agent hooks write session mappings
under ~/.cmuxterm/. On restore, cmux rebuilds the layout first, then runs the
supported agent's native resume command when automatic agent resume is enabled.
Read the full guide at https://cmux.com/docs/session-restore.
Star History
Contributing
Ways to get involved:
Community
Founder's Edition
cmux is free, open source, and always will be. If you'd like to support development and get early access to what's coming next:
Get Founder's Edition
- Prioritized feature requests/bug fixes
- Early access: cmux AI that gives you context on every workspace, tab and panel
- Early access: iOS app with terminals synced between desktop and phone
- Early access: Cloud VMs
- Early access: Voice mode
- My personal iMessage/WhatsApp
License
cmux is open source under GPL-3.0-or-later.
If your organization cannot comply with GPL, a commercial license is available. Contact [email protected] for details.
