OpenAI's Codex desktop app is now available on Windows via the Microsoft Store, roughly a month after the macOS version landed. Over 500,000 developers were on the waitlist.
The big deal here isn't just Windows compatibility. OpenAI built what it calls the first Windows-native agent sandbox for AI coding tools. It uses OS-level controls (restricted tokens, filesystem ACLs, a dedicated sandbox user) to block writes outside your working folder and kill outbound network traffic unless you approve it. The sandbox is open source. Developers can run Codex natively with PowerShell, Command Prompt, or Git Bash, or fall back to WSL if they prefer Linux tooling.
OpenAI is calling Codex "the only coding agent with a first-class Windows experience," per a spokesperson, pointing to Stack Overflow's 2025 survey showing nearly half of professional developers use Windows. That framing aside, the app mirrors the Mac version's feature set: multi-agent coordination, parallel workflows, Skills for reusable task bundles, and Automations for scheduled work. Windows-specific additions include a WinUI skill for developers building Windows apps.
Adoption numbers are hard to ignore. The Mac app hit a million downloads in its first week, and weekly active users now sit at 1.6 million. Codex usage has roughly doubled since GPT-5.2-Codex shipped in mid-December. The app is available across all ChatGPT tiers, and OpenAI is temporarily doubling rate limits on paid plans through April 2.
Bottom Line
OpenAI's Codex Windows app ships with a first-of-its-kind open-source native sandbox and targets the roughly 50% of professional developers on Windows.
Quick Facts
- Available via Microsoft Store as of March 4, 2026
- 500,000+ developers on Windows waitlist before launch
- Mac app: 1 million downloads in first week, 1.6 million weekly active users
- Native sandbox is open source, uses restricted tokens and filesystem ACLs
- Paid plan rate limits doubled through April 2, 2026
