Poetry Python Package Manager

Poetry is a free and open-source tool for dependency management and packaging in Python, designed to replace pip, virtualenv, and setup.py with a single, unified workflow. Created by Sebastien Eustace (sdispater) in 2018, Poetry has become one of the most popular Python project management tools, used by thousands of projects including FastAPI, Pydantic, and Celery. Key features: dependency management: Poetry resolves and installs project dependencies declared in pyproject.toml (following PEP 518). Dependencies are resolved semantically (e.g., requests ^2.28.0) using a SAT solver, detecting conflicts and suggesting resolutions. Poetry uses a deterministic lock file (poetry.lock) that pins exact versions of all dependencies including transitive ones, ensuring reproducible installs. Virtual environments: Poetry automatically creates and manages virtual environments for each project. Virtual environments can be created inside the project directory or in a central cache location. The poetry shell command activates the virtual environment. Packaging: Poetry handles building both source distributions (sdist) and wheel distributions (bdist_wheel) without needing setup.py or setup.cfg. The build process is configured entirely in pyproject.toml. Publishing: Poetry can publish packages to PyPI or custom repositories with authentication. The poetry publish command uploads built distributions. Dependency groups: Poetry supports optional dependency groups (e.g., dev, test, docs) that can be installed independently. Groups replace the old requirements-dev.txt pattern. Scripts and plugins: console entry points for CLI tools. Poetry plugins for extending functionality. pyproject.toml: the single configuration file for the project, declaring metadata (name, version, description, authors), dependencies, development dependencies, scripts, and build system. Version management: Poetry follows Semantic Versioning and can automatically bump version numbers. Go. MIT.