Packaging & Distribution

Introduction

Ship Python code as a wheel on PyPI using pyproject.toml + build + twine (or modern uv publish, hatch publish).

Understanding the topic

Core concepts to understand:

• pyproject.toml drives everything (PEP 621).
• python -m build creates wheel + sdist.
• twine upload dist/* publishes to PyPI.
• Semver: 1.2.3 = major.minor.patch.

Syntax reference

Visual flow / code:

[project]
name = "my-lib"
version = "0.1.0"
description = "Cool stuff"
requires-python = ">=3.10"
dependencies = ["requests>=2.31"]

[project.urls]
Homepage = "https://github.com/me/my-lib"

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

# Build & publish
$ python -m build
$ twine upload dist/*

Execution workflow

Real-world use

Once published to PyPI, anyone can pip install my-lib. Major orgs run private indexes (Artifactory, AWS CodeArtifact) for internal libs.

Best practices

• Tag releases in git matching the version.
• Use CI (GitHub Actions) to publish on tag.
• Test on TestPyPI first.

Hands-on exercise

Interview preparation — practice these questions:

• wheel vs sdist?
• Semver — what changes when?
• Why pyproject.toml?

Summary

In summary: pyproject.toml is the source of truth. build + twine (or uv) to publish.