How to run Codex on a remote server

What you need

• A Linux machine that stays on: a VPS, a cloud VM or a desktop at home.
• SSH access to it, with a key.
• Node.js on the server, and your repositories.
• Your OpenAI or ChatGPT account for Codex.

1. Install Codex on the server

ssh my-server
npm install -g @openai/codex

Then sign in. On a server with no browser, follow the Codex docs for signing in on a headless machine.

2. Bring your code

Clone your repository and set up Git so Codex can commit:

git clone git@github.com:you/your-repo.git
cd your-repo

You’ll need a deploy key or an SSH key on the server that GitHub accepts.

3. Run Codex inside tmux

tmux new -s codex
codex
# detach with Ctrl-b then d

Codex keeps working after you disconnect. Reattach from any device with tmux attach -t codex.

4. Keep it healthy

• Memory: watch it with free -h. If the agent dies overnight, it’s often the kernel killing a process that ran out of memory. Check dmesg for “Out of memory”.
• Disk: node_modules, build caches and Docker images fill small disks fast. Check with df -h.
• Restarts: after an OS update or a reboot, tmux sessions are gone. Start them again.
• Secrets: keep API keys out of your shell history and out of the repo.

The managed alternative

If you’d rather not look after a server, Cube gives you an always-on Linux computer, with an app for your Mac and the web. Sign in, install Codex in one click, and give every task its own worktree. SSH is set up for you, and you can check in from your phone. To drive it from the Codex app on your Mac, see Connect the Claude and Codex apps.