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Modern Python Workflow with UV

•Ville Pakarinen

Python packaging has historically been a fragmented mess between pip, venv, and pyenv. Developers often spend more time managing environments than writing code, and this is where uv a fast Python package comes to help.

What is uv?

Developed by Astral (the creators of Ruff), uv is a single executable designed to replace your entire Python toolchain that acts as:

  • Package Manager (replacing pip)
  • Environment Manager (replacing venv)
  • Python Version Manager (replacing pyenv)
  • Tool Runner (replacing pipx)

Why use it?

  1. Unmatched Speed It is 10–100x faster than pip. On a cold cache, it installs packages in milliseconds. On a warm cache, it is virtually instantaneous because it leverages a global module cache and hardlinks.

  2. Zero Dependencies Since it is written in Rust, uv is a standalone binary. You don’t even need Python installed to install uv, it can install Python for you.

  3. Universal Lockfiles It generates a uv.lock file that ensures your environment is identical across your local machine, CI/CD, and production servers (AWS).

  4. Modern Defaults It supports pyproject.toml natively and handles dependency resolution without "backtracking" hangs common in older tools.

How it works

1. Project Initialization

Start a new project with a standard structure:

uv init my-project
cd my-project

2. Managing Dependencies

Adding a package creates a virtual environment (.venv) and updates lockfile:

uv add fastapi pydantic

3. Running Scripts

You can run a script in a temporary environment without "activating" anything:

uv run main.py

4. Managing Python Versions

Need a specific version for a training job?

uv python install 3.12
uv python pin 3.12

The Verdict

uv replaces the frustration of broken environments with a single, fast tool that just works. It takes the guesswork out of Python project management letting you focus on building your features instead of fixing your dependencies.