Ghostty vs cmux: A Guide to Choosing Your Modern Terminal

🌏 中文版

If you’ve been looking for an iTerm2 replacement, Ghostty is the standard answer. But if you’re running multiple AI coding agents simultaneously, cmux is worth a closer look. This post breaks down the design philosophy, feature differences, and how to choose between the two.

Ghostty

Ghostty was created by Mitchell Hashimoto, founder of HashiCorp, and quickly gained traction in the developer community after its public release in late 2024. Its positioning is clear: be fast, feature-complete, and native — not two out of three.

Design Philosophy

Most terminals make trade-offs between speed, features, and native experience. Ghostty’s approach is to extract the core into libghostty (a C-compatible library), wrap it with Swift/AppKit on macOS and GTK on Linux, and use Metal (macOS) or OpenGL (Linux) for rendering. This lets it achieve GPU-accelerated rendering while maintaining a truly native UI — unlike Electron-based terminals that simulate native feel using web technologies.

Core Features

• GPU-accelerated rendering: The only terminal on macOS that supports both Metal and ligatures simultaneously — iTerm2 falls back to CPU rendering when ligatures are enabled
• Zero-config out of the box: Sensible defaults that just work, including built-in Nerd Fonts support — install and go
• Native tabs and split panes: Built with actual system UI components, not custom-drawn widgets
• Deep macOS integration: Quick Look, Force Touch, Secure Input API, and a drop-down terminal (Quake mode)
• Rich themes: Hundreds of built-in themes with automatic light/dark mode switching
• libghostty: Exposed as an embeddable library, enabling other terminal tools to build on top of this core

Limitations

macOS doesn’t have a system-level “default terminal” setting, and Ghostty currently doesn’t have a built-in option to set itself as default (open feature request). If you want .command or .tool scripts to open in Ghostty by default, you’ll need to manually configure file associations in Finder.

brew install --cask ghostty

cmux

cmux is developed by manaflow-ai, positioned as “a terminal for AI coding agents.” It uses libghostty under the hood — also Swift + AppKit — so rendering performance is on par with Ghostty, but with an entire layer of agent workflow features built on top.

Design Philosophy

cmux describes itself as a primitive, not a solution. It provides the building blocks — terminal, browser, notifications, workspaces, split panes, CLI control interface — without prescribing a specific workflow. What agents you run and how you compose them is entirely up to you.

Core Features

• Vertical sidebar tabs: Each workspace shows live git branch, PR status, listening ports, and latest notifications — at a glance you can see which agent is busy with what
• Smart notification system: Supports OSC 9/99/777 terminal sequences; when an agent is waiting for input, the corresponding pane lights up with a blue ring and the tab highlights — Cmd+Shift+U jumps to the latest unread
• Embedded scriptable browser: Agents can screenshot the DOM, grab element refs, click, fill forms, and execute JS; the browser pane can be docked next to the terminal pane, letting Claude Code directly interact with your dev server
• Socket control API: The cmux CLI sends JSON messages to a Unix socket; the main app listens and updates the UI — everything is programmable: create workspaces, switch tabs, send keyboard events, open URLs
• AI agent integration: Native support for Claude Code, Codex, OpenCode, Gemini CLI, Aider, and Kiro

brew tap manaflow-ai/cmux && brew install --cask cmux

Architecture Overview

┌─────────────────────────────────────┐
│              cmux                   │
│  ┌──────────┐  ┌───────────────┐    │
│  │ Sidebar  │  │  Terminal     │    │
│  │ Tab list │  │  (libghostty) │    │
│  │ + Notifs │  ├───────────────┤    │
│  └──────────┘  │  Browser      │    │
│                │  (scriptable) │    │
│                └───────────────┘    │
│         Socket API / CLI            │
└─────────────────────────────────────┘

         ↑ built on top of

┌─────────────────────────────────────┐
│           libghostty                │
│     (GPU rendering / terminal core) │
└─────────────────────────────────────┘

Summary

These two tools are not competitors — cmux is literally built on Ghostty’s shoulders.

Choose Ghostty if you want a fast, zero-config, cross-platform terminal for everyday use and you’re tired of iTerm2.

Choose cmux if you’re running multiple AI agents simultaneously (Claude Code, Codex, etc.), need to know which agent is waiting for you, need agents to directly control a browser, or need to script and automate your entire workspace.

References

• Ghostty official site
• Ghostty - About
• Ghostty - Features
• GitHub - ghostty-org/ghostty
• How to make Ghostty the default terminal? (GitHub Discussion)
• Add Option to Set Ghostty as Default Terminal on macOS (GitHub Discussion)
• GitHub - manaflow-ai/cmux
• cmux official site
• cmux: Native macOS Terminal for AI Coding Agents - Better Stack