OpenAI acquires Astral, the Python startup whose tools run on millions of developer machines

OpenAI is acquiring Astral, the startup whose tools quietly run inside the workflows of millions of Python developers. The deal drops Astral's team into the Codex group, and the timing is not subtle: Anthropic's Claude Code has been steadily pulling professional developers away, and OpenAI needs Codex to be more than a code generator to fight back.Financial terms weren't shared. Regulatory approval is still pending before the deal officially closes.Astral makes three tools that have become unglamorous essentials—uv for dependency and environment management, Ruff for linting and formatting, and ty for type checking. Together, they cover a significant chunk of the Python development loop. The scale is striking: Astral's tools have grown from zero to hundreds of millions of downloads per month, numbers that founder and CEO Charlie Marsh says went "far beyond my most ambitious expectations at every step.

" Crucially, Marsh confirmed the open source projects aren't going anywhere—OpenAI has committed to continuing support after closing, and Astral will keep building publicly, alongside its existing community.

Claude Code has been winning over developers that codex needs

This is the context that makes the Astral deal make sense. Anthropic, nearing a $20 billion annual revenue run rate, has built real credibility with engineers through Claude Code. Cursor—another rival—is reportedly in talks to raise at a $50 billion valuation.

OpenAI's Codex has numbers worth citing: 2 million weekly active users, triple the user growth and five times the usage since January. But raw growth means less if the developers with the most influence keep gravitating elsewhere.

For OpenAI, buying the toolchain is a bet on depth over features

Marsh has always framed Astral around leverage—his founding thesis being that making the Python ecosystem even 1% more productive compounds into something massive over time. That framing maps neatly onto what OpenAI needs Codex to become.

An AI that writes code is a starting point. One that also lints it, resolves dependencies, enforces type safety, and runs checks—without the developer leaving the environment—is something developers build habits around.

Marsh put it plainly in his blog post: "It is increasingly clear to me that Codex is that frontier."The acquisition follows Promptfoo in early March and Torch in January, continuing a deliberate M&A run since OpenAI hired Google's Albert Lee to lead corporate development in December. Owning the toolchain won't close the gap with Anthropic overnight. But it's a smarter attack surface than another chat interface.