cmux vs Alacritty
Alacritty is a fast, cross-platform OpenGL terminal emulator with a deliberately lean feature set. cmux is a native macOS terminal and browser workspace built on libghostty for running many AI coding agents with notification rings, unread shortcuts, and programmable app control.
Fast terminal vs agent supervision terminal
Use Alacritty when you want a minimal, high-performance terminal and plan to compose the rest with Alacritty config, alacritty msg, shell tools, or a multiplexer. Use cmux when you want native macOS performance plus visible workspaces, Cmd+Shift+U, Cmd+Control+U, browser panes, notifications, and a socket API for agent-heavy work.
| Dimension | cmux | Alacritty |
|---|---|---|
| Primary job | Supervise many coding agents | Fast general-purpose terminal |
| Desktop stack | Native Swift/AppKit macOS app built on libghostty | Rust/OpenGL terminal emulator, not Electron/Tauri |
| Rendering engine | Built on libghostty for modern GPU-accelerated terminal rendering | OpenGL terminal renderer |
| Agent visibility | Vertical workspaces, branch and port metadata, unread state | Manual windows, shells, and external tools |
| Attention model | Notification rings, unread badges, Cmd+Shift+U, Cmd+Control+U | Visual bell, bell command, and external notification scripts |
| Automation | CLI, Unix socket API, browser automation, hooks | Config, key/mouse bindings, alacritty msg IPC, and external programs |
| Best fit | Mac developers multitasking across agents | Users who want a lean terminal primitive |
Alacritty optimizes the emulator
Alacritty is strongest when the terminal emulator should stay fast and simple. cmux starts with a fast terminal surface and adds the app-level controls agent workflows need.
cmux uses libghostty
cmux gets its terminal rendering from libghostty, the Ghostty terminal engine. That gives cmux modern terminal protocol support, GPU-accelerated rendering, terminal graphics support, and Ghostty-style configuration for fonts, themes, colors, and cursor behavior.
Notifications are built into the workflow
cmux was built by people who keep many agents running at once. Pane rings, unread badges, Cmd+Shift+U, and Cmd+Control+U turn completed or blocked agents into a keyboard-navigable review queue.
The sidebar carries context
Agent sessions need more than a prompt. cmux shows workspace names, branch context, directories, ports, latest output, and unread state so a dozen sessions stay legible.
Programmability reaches browser checks
cmux exposes terminal control and browser automation through the same socket API, so agents can run commands, inspect web pages, capture screenshots, and report status from one workspace.
FAQ
Is cmux faster than Alacritty?
They optimize different layers. Alacritty focuses on lean terminal emulation. cmux focuses on a native macOS agent workflow around a fast terminal surface.
Can Alacritty run coding agents?
Yes. Any terminal can run CLI agents. cmux adds the multitasking, notification, browser, and automation layer around those sessions.
When should I choose cmux?
Choose cmux when your bottleneck is supervising many agents, not just rendering one terminal quickly.