OpenAI's Codex app lands on Windows after topping a million Mac downloads in its first week

OpenAI has released its Codex app for Windows. Codex is an AI-powered coding tool that helps developers build software by running multiple agents asynchronously across projects, delegating repeatable tasks through Automations, and connecting agents to tools and workflows via Skills. Developers can review, guide, and step into agent work without losing context.

For the Windows version, OpenAI built its own sandbox that operates at the OS level with restricted tokens, file system access rights, and dedicated sandbox user accounts. This lets AI agents run directly in Windows environments like PowerShell without forcing developers to switch to WSL or virtual machines. OpenAI has published the sandbox code as open source on GitHub.

The Windows app arrives a few weeks after the Mac version, which was downloaded over a million times in its first week, according to OpenAI. More than 500,000 developers had already signed up for the Windows waiting list. OpenAI says Codex now has over 1.6 million weekly active users total. The app is available across all ChatGPT plans.