OpenAI agreed on March 19, 2026 to acquire Astral, the company behind the open-source Python developer tools uv, Ruff and ty. Astral founder Charlie Marsh announced the agreement on the company's blog, saying the team would join OpenAI as part of Codex, its AI coding product.
Neither company disclosed the price or other financial terms. The transaction is subject to customary closing conditions, including regulatory approval, according to reports of the announcement. OpenAI said it would continue to support Astral's tools as open-source projects after closing and use them internally to improve Codex.
After the deal, the Astral team plans to keep developing its tools, look at how they can work more closely with Codex, and think more broadly about how software is built, Marsh wrote.
What Astral built
Astral makes three tools for Python programmers, all written in Rust. uv is a package and project manager that installs dependencies and manages environments. Ruff is a linter and code formatter. ty is a type checker. The Register reported that the tools run faster than older Python-based equivalents such as pip.
Ruff came first; Marsh wrote it before forming the company. According to Marsh, Astral's tools now reach hundreds of millions of downloads a month, and he described the toolchain as foundational to modern Python development.
When Astral announced its existence in April 2023, it said the team had three people working remotely across North America and Europe. Its early members included Marsh, the original author of Maturin and a core contributor to Rome.
“I started Astral to make programming more productive.”
Why OpenAI is buying
OpenAI presented the deal as part of a plan to take Codex beyond writing code. In its announcement it said the goal for Codex is to move beyond AI that only generates code, and that it would connect Astral's tools with Codex after closing so AI agents can work with them. Thibault Sottiaux, who leads Codex at OpenAI, said bringing Astral's expertise and ecosystem in-house would help make Codex an agent for the whole software development lifecycle, heise reported.
Codex has grown quickly in 2026. Heise reported that its user base had tripled since the start of the year to more than two million weekly active users. The Register described the purchase as both a product deal and a talent acquisition, since the Astral team moves into the Codex group.
The deal is one of several by OpenAI. Heise noted that the company had recently agreed to acquire Promptfoo and Neptune, and that it bought Software Applications Incorporated at the end of 2025.
The founder and the funding
Marsh founded Astral in 2022, according to The Register. In April 2023 the company announced a $4 million seed round led by Accel, with Caffeinated Capital and individual backers including Vercel's Guillermo Rauch, Docker's Solomon Hykes, Sentry's David Cramer, Wes McKinney of Voltron Data and Nick Schrock of Elementl.
In his post on the OpenAI deal, Marsh thanked Casey Aylward of Accel, who led the seed and Series A rounds, and Jennifer Li of Andreessen Horowitz, who led the Series B. The amounts of the Series A and Series B were not disclosed.
"I started Astral to make programming more productive," Marsh wrote. He said open source sat at the centre of the company's impact, and told users: "We'll keep building in the open, alongside our community."
Questions over open source
Because uv and Ruff are used across the Python ecosystem, much of the reaction focused on whether they would remain independent. Developer Simon Willison wrote that one bad version of the deal would be if OpenAI used its ownership of uv as leverage against competitors, The Register reported. Willison also suggested that Astral's Series A and B investors might exchange their stakes for OpenAI shares.
The Register compared the purchase with Anthropic's acquisition of Bun, the JavaScript runtime and package manager, in December 2025. Both deals put widely used open-source developer infrastructure inside an AI lab that sells a coding agent.
Both OpenAI and Astral said the tools would remain open source.
