TL;DR

cmux is a Ghostty-based terminal with vertical tabs, notifications, and in-app browser, built for multitasking with coding agents.

cmux is trusted by thousands of builders from Nvidia, Google, OpenAI, and more. In two weeks, we’ve gained 9.5k GitHub stars.

https://github.com/manaflow-ai/cmux

https://www.youtube.com/watch?v=i-WxO5YUTOs

Hey, we’re Austin and Lawrence.

The future is pointing towards an IDE-less world. In fact, the best engineers have already stopped using VS Code and Cursor.

Boris Cherny, the creator of Claude Code, has not opened an IDE since last November. No one knows what the best workflow looks like yet, but it has never been more urgent to experiment with AI or be left behind.

But our current tools aren’t built for this. If you try running multiple Claude Code or Codex sessions in a standard terminal, you’ll find yourself in the midst of chaos. On the flip side, GUI orchestrators lock you in and lack the flexibility for experimentation.

That’s why we built cmux: an open-source terminal primitive for exploring the future of agent-driven workflows.

We wanted a lightning-fast native macOS (Swift/AppKit) terminal with features you need for managing fleets of coding agents:

• Vertical tabs
• Blue rings around panes that need attention
• Built-in browser
• Based on Ghostty

cmux also has a built-in CLI that allows coding agents to command cmux’s browser, create new workspaces, and start off other agents in new terminals. AI can use cmux exactly like you would.

https://www.youtube.com/watch?v=XKc1cVCFLDQ

The zen of cmux

cmux is not prescriptive about how developers hold their tools. It's a terminal and browser with a CLI, and the rest is up to you.

cmux is a primitive, not a solution. It gives you a terminal, a browser, notifications, workspaces, splits, tabs, and a CLI to control all of it. cmux doesn't force you into an opinionated way to use coding agents. What you build with the primitives is yours.

The best developers have always built their own tools. Nobody has figured out the best way to work with agents yet, and the teams building closed products definitely haven't either. The developers closest to their own codebases will figure it out first.

Give a million developers composable primitives and they'll collectively find the most efficient workflows faster than any product team could design top-down.

cmux is free, open-source (AGPL), and already trusted by thousands of builders from Nvidia, Google, OpenAI, and more. Developers build or port their own custom harnesses and orchestrators on top of cmux.

https://github.com/manaflow-ai/cmux

Traction

In two weeks, cmux grew from zero to 3.5k GitHub stars.

We peaked at #2 on Hacker News: https://news.ycombinator.com/item?id=47079718

Our X launch went viral: https://x.com/lawrencecchen/status/2026729219154378912

Mitchell Hashimoto, the creator of Ghostty and founder of HashiCorp, shouted out cmux on X.

Nick Schrock, the creator of Dagster and GraphQL:

Edward Grefenstette, Director of Research at Google DeepMind:

Many Japanese fans:

How you can help

Star our GitHub repo: https://github.com/manaflow-ai/cmux

Try cmux: https://www.cmux.com/

Share cmux with your friends: send feedback to founders@manaflow.ai.