Python Developer Tooling Handbook – Virtual-Environments

uv 0.8 Release: Automatic Python Installation to PATH

Tim Hopper — Sat, 19 Jul 2025 09:27:00 -0400

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Check out our guide to upgrading uv

uv 0.8 stabilizes one of the most significant workflow improvements in Python tooling: automatic installation of Python executables to your PATH. This means you can finally install Python versions with uv python install and use them system-wide without wrestling with environment activation.

Global Python Access Without the Hassle

The headline feature addresses a long-standing frustration in Python development. When you run:

Managing Python Versions In Your uv Projects

Tim Hopper — Wed, 25 Jun 2025 10:09:00 +0000

One of the many ways the package manager uv has changed Python is by making it painless to install and run different versions of the Python interpreter.

That said, I’ve occasionally gotten tripped up configuring this correctly in my development environments. I’ve written a few articles to try to clarify things:

How to install Python with uv. Before you can pin a Python version, you need to have it installed.
What is a .python-version file? Not unique to uv, a .python-version file specifies which Python version should be used for a particular project or directory.
.python-version vs requires-python in pyproject.toml. The former is for development environments, while the latter is for package metadata.
How to change the python version of a uv project. If uv run isn’t using the version of Python you expected or wanted, here is what you can do.

The goal of the handbook is to help you understand the ecosystem of tools used to make Python development easier and more productive. What are some missing topics you’d like to see included?

Why Use uv Projects Instead of requirements.txt?

Tim Hopper — Wed, 19 Feb 2025 09:17:00 +0000

This is an excerpt from the forthcoming Python Developer’s Tool Handbook. The handbook provides comprehensive guidance on Python tooling and best practices for modern Python development.

The Python ecosystem offers two main approaches to managing project dependencies: the traditional requirements.txt file and the newer pyproject.toml standard. Understanding the strengths and limitations of each helps inform better choices for Python development.

Flexible Python Version Management with uv and tox

Tim Hopper — Wed, 12 Feb 2025 10:20:00 +0000

When working with Python projects that use tox for testing, you may encounter version mismatch errors like:

lint-format: skipped because could not find python interpreter with spec(s): python3.8

This happens when tox expects a specific Python version that isn’t available in your environment. Traditionally, this would require:

Require pip to install packages in virtual environment

Tim Hopper — Mon, 04 Mar 2024 15:34:08 +0000

A frequently heard piece of advice in improving Python development practice is using virtual environments to install dependencies. Virtual environments isolate your dependencies per project to protect you from annoying version conflicts.

You can restrict pip to only install in virtual environments by running

pip config set global.require-virtualenv true

This updates your global pip config file.

Quick start guide for Python development on a Mac

Tim Hopper — Mon, 05 Feb 2024 00:00:00 +0000

Note

For a modern approach, consider uv, which handles Python installation, project management, and dependency management in a single tool. The pyenv + Poetry workflow described below remains valid, but uv offers a more streamlined experience.