cmux

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.