Open source, several ways to install
The Codex repository is published under the Apache-2.0 licence. You can install it with npm install -g @openai/codex, brew install --cask codex, or the standalone installer: curl -fsSL https://chatgpt.com/codex/install.sh | sh on macOS and Linux, and a PowerShell installer on Windows. Run codex in a project and choose Sign in with ChatGPT, or use an API key.