Astral bets Rust can rewrite Python's toolchain; OpenAI acquires it for Codex in 2026

A developer-tools company building open-source, Rust-based replacements for Python's toolchain: Ruff (linter/formatter), uv (package manager) and ty (type checker/language server).

That Python's toolchain — linting, packaging, type checking — could be rebuilt in Rust to run 10–100x faster, and open source would make them the ecosystem's defaults.

$4M seed led by Accel (April 2023); later undisclosed Series A (Accel) and Series B (Andreessen Horowitz).

Charlie Marsh built Ruff as a side project to test a theory: that Python tooling could be much, much faster. After Ruff passed one million monthly downloads and 12,000 stars and was adopted by Airflow, FastAPI, Pandas and SciPy, he incorporated Astral in April 2023 with a $4M seed led by Accel to keep building 'more Ruff-like things.'

Astral shipped uv, a package manager that replaces pip, pip-tools, pipx, poetry and virtualenv with 10–100x speedups, then ty, a Rust type checker whose December 2025 beta post claims 10–60x speedups over mypy and Pyright. Runa Capital's ROSS Index tracked ty to 11.2K stars (11.2x growth) in Q3 2025, and Astral began commercializing with a paid package registry after undisclosed Series A and Series B rounds led by Accel and a16z.

On 2026-03-19 OpenAI announced it will acquire Astral, with the team joining the Codex organization; Astral says its open-source tools (uv, Ruff, ty) will keep shipping after closing, which is subject to regulatory approval.

A 10–100x speedup in the most-used developer tools is instantly measurable, so word of mouth did the selling.

Open source removed adoption risk: teams could switch linter, package manager or type checker without lock-in, making default achievable.

Each tool reused the same Rust foundation and community, so the second and third products launched with distribution already built.

The open-core path — free tools, paid registry — gave the company revenue optionality that made it attractive to OpenAI.

Pick the slowest part of a developer workflow and rebuild it 10–100x faster in the open: adoption compounds on measurable speed, and each hit funds the next tool until one company owns the toolchain.

As of September 2026 Astral has agreed to join OpenAI: the acquisition was announced March 19, 2026, with the team moving into the Codex organization and OpenAI committing to keep supporting the open-source tools after closing. Until the deal closes — subject to regulatory approval — Astral remains an independent company, and its tools (Ruff, uv, ty) continue to ship, with ty's stable release expected during 2026. The open-source portfolio now spans linting, packaging and type checking, with hundreds of millions of monthly downloads.