What to use.
And why
Python's tooling is a maze of overlapping tools, cautious official docs, and stale blog posts. This handbook tells you what to use today, and why.
New to Python and just need it running? Start with How to Install Python. It tells you what to install on macOS, Windows, or Linux, and what to ignore.
The handbook covers packaging, linting and formatting, testing, type checking, and dependency management with opinionated recommendations and honest trade-offs. Each tool’s Reference page links to its official documentation; the handbook complements those docs, the Python Packaging User Guide, and the Scientific Python Library Development Guide, not replaces them.
Starting or standardizing a project? The Modern Python Tooling Checklist puts these defaults on one page.
Topic hubs
Curated entry points for the tools and tasks at the heart of modern Python development.
Popular pages
Browse by section
- Tutorial Step-by-step guides for setting up tools and workflows.
- How To Practical solutions to specific problems.
- Explanation Context and background for understanding the ecosystem.
- Reference Tool-by-tool technical descriptions.
Feedback on any page is welcome via the form at the bottom.
Recent Blog Posts
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I'm Running for the Python Packaging Council
The inaugural Python Packaging Council election has 17 nominees competing for 5 seats. I'm one of them.
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uv 0.12 Makes Every New Project a Package
uv init now writes a src/ layout with a build system and a console script. What changed, why it changed back, and how to get the flat main.py layout.
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Ruff 0.16.0 Enables 7x More Rules by Default
Ruff's first default-ruleset expansion since v0.1.0 adds 354 rules. What changes when you upgrade, which new categories are on, and how to migrate cleanly.
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PyPI Now Rejects New Files on Releases Older Than 14 Days
PyPI blocks new file uploads to releases older than 14 days, closing an attack that could poison a pinned version without changing its number.
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uv's Malware Check: What It Blocks and What It Misses
Turn on uv's install-time malware check in pyproject.toml to block known-malicious packages before any of their code runs.
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ty now checks Pydantic like Pydantic does
ty 0.0.57 added first-class Pydantic support: lax and strict validation modes, ConfigDict parsing, and Field metadata. Here is what it checks and how it changes the ty vs Pyrefly choice.
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Python 3.15 makes UTF-8 the default encoding
Python 3.15 enables UTF-8 mode by default. On Windows, text-mode open() and subprocess calls without an explicit encoding switch from the system code page to UTF-8. Here is what breaks and how to audit your codebase.
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uv Wants to Secure Your CLI Tools
uv is building toward vulnerability scanning for globally installed CLI tools. A preview feature in 0.11.25 starts by writing a lockfile for each tool you install.
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uv Solved the Packaging UX, Not Packaging
uv made Python packaging fast and pleasant for everyday use. But the problems the new Packaging Council will tackle, like GPU wheels, external dependencies, and lockfile standards, live in layers uv doesn't touch.
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Pixi Can Now Build Packages From Source
Pixi Build brings PEP 517-style build backends to the conda ecosystem, letting pixi build Python, Rust, and mixed-language packages from source inside a single project. SciPy, Xarray, Dask, and CPython are early adopters.