cmux
The terminal built for
Features
- - Vertical tabs : sidebar shows git branch, working directory, ports, and notification text
- - Notification rings : panes light up when agents need attention
- - In-app browser : split a browser alongside your terminal with a scriptable API
- - Split panes : horizontal and vertical splits within each tab
- - Scriptable : CLI and socket API for automation and scripting
- - GPU-accelerated : powered by libghostty for smooth rendering
- - Lightweight : native Swift + AppKit, no Electron
- - Keyboard shortcuts : extensive shortcuts for workspaces, splits, browser, and more
FAQ
How does cmux relate to Ghostty?
cmux is not a fork of Ghostty. It uses{" "} libghostty{" "} as a library for terminal rendering, the same way apps use WebKit for web views. Ghostty is a standalone terminal; cmux is a different app built on top of its rendering engine.
What platforms does it support?
macOS only, for now. cmux is a native Swift + AppKit app.
What coding agents does cmux work with?
All of them. cmux is a terminal, so any agent that runs in a terminal works out of the box: Claude Code, Codex, OpenCode, Gemini CLI, Kiro, Aider, Goose, Amp, Cline, Cursor Agent, and anything else you can launch from the command line.
How do notifications work?
When a process needs attention, cmux shows notification rings around panes, unread badges in the sidebar, a notification popover, and a macOS desktop notification. These fire automatically via standard terminal escape sequences (OSC 9/99/777), or you can trigger them with the{" "} cmux CLI{" "} and{" "} Claude Code hooks.
Can I customize keyboard shortcuts?
Terminal keybindings are read from your Ghostty config
file (~/.config/ghostty/config).
cmux-specific shortcuts (workspaces, splits, browser, notifications) can be
customized in Settings. See the{" "}
default shortcuts{" "}
for a full list.
How does it compare to tmux?
tmux is a terminal multiplexer that runs inside any terminal. cmux is a native macOS app with a GUI: vertical tabs, split panes, an embedded browser, and a socket API are all built in. No config files or prefix keys needed.
Is cmux free?
Yes, cmux is free to use. The source code is available on{" "} GitHub.