cmux — The terminal built for multitasking

What

cmux is a macOS terminal application designed for multitasking, especially for developers running coding agents and parallel terminal-based workflows. It is built as a native Swift and AppKit app on top of libghostty for terminal rendering, and combines terminal panes, vertical tabs, notifications, and an embedded browser in one interface.

The product appears positioned as a GUI-first alternative to combining a standard terminal with tmux and separate browser windows. It serves users who manage multiple tasks, branches, worktrees, or agent sessions at once and need faster switching, clearer attention signals, and automation through a CLI and socket API.

Features

• Vertical tabs with contextual metadata: The sidebar shows items like git branch, working directory, ports, and notification text to make parallel sessions easier to identify and manage.
• Notification rings and alerts: Panes can light up when a process needs attention, with badges, a notification popover, and macOS desktop notifications to reduce missed agent or task events.
• Embedded browser in split view: An in-app browser can run alongside terminal panes, which is useful for keeping docs, pull requests, or web tools visible within the same workspace.
• Horizontal and vertical split panes: Each tab supports multiple pane layouts, helping users monitor several shells or tools without opening separate terminal windows.
• Automation via CLI and socket API: Scriptable controls support workflow automation and custom tooling, which is valuable for agent-driven or repeatable development tasks.
• Native, GPU-accelerated macOS app: Built with Swift, AppKit, and libghostty rather than Electron, cmux emphasizes lightweight operation and smooth terminal rendering.

Helpful Tips

• Evaluate fit by workflow complexity: cmux is most relevant for users who regularly run multiple terminal sessions, coding agents, or worktrees; simpler single-shell workflows may benefit less.
• Check platform constraints early: The page states macOS only, so teams with mixed operating systems should treat adoption as individual rather than standardized unless broader platform support appears later.
• Plan around existing Ghostty configuration: Terminal keybindings are read from the Ghostty config, so current Ghostty users may have a smoother setup and more predictable keyboard behavior.
• Use notifications intentionally: The attention model depends on terminal escape sequences or explicit triggering through the cmux CLI and hooks, so implementation quality may vary across tools and scripts.
• Compare against tmux by interface needs, not ideology: cmux is presented as a native GUI with built-in panes, browser, and automation, whereas tmux remains more portable and terminal-native.