Poetry

Dependency management and packaging tool for Python that unifies project setup, dependency resolution, building, and publishing under a single CLI. Uses a lock file for deterministic installs and an exhaustive resolver that either finds a solution or provides a detailed explanation when conflicts occur.

Widely adopted for Python applications and libraries. Poetry differentiates from pip and setuptools by combining dependency management, virtualenv handling, and packaging in one tool, with a single pyproject.toml as the project definition. Poetry 2.0 added PEP 621 support for improved interoperability with other tools.

Key capabilities:

• Deterministic installs via lock file and exhaustive dependency resolver
• Virtualenv isolation, either auto-created or using configured environments
• Build source distributions and wheels with a single command
• Publish to PyPI or private repositories
• Dependency tree inspection and plugin system for extensibility

Developers use Poetry to manage dependencies for web apps, CLI tools, and libraries, to ensure reproducible builds across dev and CI, and to simplify publishing to PyPI. The intuitive CLI and sensible defaults fit into existing Python workflows without extra configuration.