OpenAI has released a Windows version of its Codex desktop app, making its AI coding agent available to Windows developers through the Microsoft Store. The release, in the first week of March 2026, follows the launch of the Mac app in February.
The Windows app adds a native sandbox, an isolated environment in which the agent can run and test code without touching the rest of the system, along with support for PowerShell, the command-line shell used on Windows. According to OpenAI, the sandbox is meant to let developers delegate tasks to the agent with less risk of unintended changes to their machines.
Rapid adoption on the Mac
Codex has grown quickly since OpenAI repositioned it as an agent that can take on multi-step coding tasks rather than a simple autocomplete tool. The Mac app reached one million downloads in its first week after its February launch, OpenAI said, and by the end of February the product had about 1.6 million weekly active users.
Those figures come from OpenAI, but they are consistent with the broader pattern across the industry, where coding has become the most commercially important use of large language models. Developers were among the first professional groups to adopt AI assistants at scale, and vendors now compete on how much of a task an agent can complete autonomously.
A crowded field
OpenAI faces strong competition. Anthropic’s Claude Code has become a major presence in enterprise development teams, Google offers Gemini-based coding tools, and GitHub Copilot, owned by Microsoft, remains widely deployed. Startups such as Cursor have also built large businesses on AI-assisted coding.
The decision to ship Codex through the Microsoft Store is notable given the sometimes strained relationship between OpenAI and Microsoft, which is both OpenAI’s largest investor and, through GitHub, one of its competitors in developer tools. For now, the store listing gives OpenAI a straightforward distribution channel to the large base of Windows developers who had been limited to the command-line version of Codex.
The competition in coding tools is increasingly about ecosystems rather than individual features: which company’s agent developers install first, which integrates best with their repositories and cloud accounts, and which their employers are willing to pay for. The Windows release closes a gap in Codex’s reach on that front.
