# Bernát Gábor — Python packaging, tox, virtualenv & open source

> Engineering notes from Bernát Gábor, PyPA maintainer of tox, virtualenv, pipx, filelock and platformdirs: Python packaging, typing and supply chain security.

Maintained by Bernát Gábor. Every page links to its raw-markdown source; append it to any page URL to fetch clean markdown.

## Posts

- [How turbohtml makes Python HTML work 3-22x faster](https://bernat.tech/posts/blazing-fast-html-parser/index.md): C removes Python's loop overhead. turbohtml skips clean spans, allocates exact buffers, reuses indexes, and trains the compiler.
- [Deterministic Multithreaded Testing in Python with blanket](https://bernat.tech/posts/blanket-deterministic-threading/index.md): How blanket gives Python tests deterministic control over thread scheduling, and why that matters now that free-threaded Python is shipping.
- [PyCon US 2026 Packaging Summit Recap](https://bernat.tech/posts/pycon-us-2026-packaging-summit-recap/index.md): Notes from the PyCon US 2026 Packaging Summit: Emma Smith on Wheel 2.0 and Zstandard, Mike Fiedler on PyPI abuse, PEP 772, mobile wheels and the roundtables.
- [PyCon US 2026 Typing Summit Recap](https://bernat.tech/posts/pycon-us-2026-typing-summit-recap/index.md): Notes from the PyCon US 2026 Typing Summit: Pyrefly and AI agents, ty constraint sets, tensor shape types, intersection types, PEP 827 and Typing Council Q&A.
- [PyTexas 2026 Recap](https://bernat.tech/posts/pytexas-2026-recap/index.md): Notes from PyTexas 2026: Hynek on domain modeling, Dawn Wages on specialization, MCP security, PEP 810 lazy imports, free-threading, Ruff, ty and uv.
- [Defense in Depth: A Practical Guide to Python Supply Chain Security](https://bernat.tech/posts/securing-python-supply-chain/index.md): Securing Python dependencies from ingestion to deployment: linting, pinning, vulnerability scanning, SBOMs and attestations.
- [Version numbers: how to use them?](https://bernat.tech/posts/version-numbers/index.md): Comparing semantic versioning, calendar versioning, and ZeroVer for Python libraries and when to use each
- [Python packaging - Growing Pains](https://bernat.tech/posts/growing-pain/index.md): Lessons learned from the rollout of PEP-517 and PEP-518 in pip, and the growing pains of changing Python's build system
- [Python packaging - Past, Present, Future](https://bernat.tech/posts/pep-517-518/index.md): A detailed look at how pip install works, from distutils to setuptools to PEP-517 and PEP-518
- [The state of Python Packaging](https://bernat.tech/posts/pep-517-and-python-packaging/index.md): An overview of Python package types, the packaging ecosystem, and how PEP-517 modernizes the build process
- [The state of type hints in Python](https://bernat.tech/posts/the-state-of-type-hints-in-python/index.md): How Python type hints work since PEP 484: annotations, type comments, stub files, protocols, mypy, and gotchas from str to contravariant arguments.

## Pages

- [Open source projects](https://bernat.tech/oss/index.md): Bernát Gábor — Bloomberg software engineer in Los Angeles and primary maintainer of the PyPA projects tox, virtualenv, pipx, filelock, and platformdirs.
- [Talks](https://bernat.tech/talks/index.md): Recorded talks by Bernát Gábor at PyCon US, EuroPython, PyTexas and PyLondinium, 2018 to 2025: Python packaging, tox, virtualenv and type hints.
- [Now](https://bernat.tech/now/index.md): What Bernát Gábor is working on right now.