# PDM — Modern Python Package and Dependency Manager

> PDM is a Python package and dependency manager that supports PEP 582 and PEP 621 standards, offering fast resolution, lockfiles, and build backends without requiring virtualenvs.

## Install

Save as a script file and run:

# PDM — Modern Python Package and Dependency Manager

## Quick Use
```bash
# Install PDM
pip install pdm
# Initialize a new project
pdm init
# Add dependencies
pdm add requests flask
pdm run python app.py
```

## Introduction
PDM is a modern Python package manager created by Frost Ming. It follows PEP 621 for project metadata in `pyproject.toml` and optionally supports PEP 582 for local package installation without virtual environments. PDM provides fast dependency resolution, cross-platform lockfiles, and a flexible build backend system.

## What PDM Does
- Resolves and installs Python dependencies with a fast resolver
- Generates reproducible cross-platform lockfiles (`pdm.lock`)
- Manages virtual environments automatically or uses PEP 582 local packages
- Supports multiple Python versions and allows switching between them
- Builds and publishes packages to PyPI with pluggable build backends

## Architecture Overview
PDM's resolver uses a backtracking algorithm that evaluates dependency constraints across all transitive packages. It writes a lockfile with pinned versions, hashes, and platform markers. At install time, it reads the lockfile, downloads wheels in parallel, and installs them into either a virtual environment or a `__pypackages__` directory (PEP 582). The CLI is plugin-extensible, and the build system delegates to any PEP 517-compatible backend.

## Self-Hosting & Configuration
- Install via pip, pipx, Homebrew, or the official installer script
- Project configuration uses standard `pyproject.toml` with `[project]` and `[tool.pdm]` sections
- Python interpreter selection via `pdm use` or `.python-version` file
- Lockfile strategy is configurable: cross-platform (default) or platform-specific
- CI integration via `pdm install --frozen-lockfile` for deterministic builds

## Key Features
- PEP 621 compliance: standard `[project]` table for metadata instead of proprietary formats
- Dependency groups for dev, test, and optional extras with fine-grained control
- Script runner (`pdm run`) with custom script definitions in pyproject.toml
- Plugin system for extending commands, resolvers, and installers
- Centralized package cache to save disk space across projects

## Comparison with Similar Tools
- **pip** — basic installer without lockfiles or resolver guarantees; PDM adds resolution and lockfiles
- **Poetry** — similar feature set but uses non-standard `[tool.poetry]` metadata; PDM follows PEP 621
- **uv** — ultra-fast Rust-based installer; PDM is pure Python with a broader feature scope
- **Hatch** — focuses on project lifecycle and environments; PDM emphasizes dependency resolution
- **Pipenv** — Pipfile-based with slower resolution; PDM is faster and standards-compliant

## FAQ
**Q: Does PDM require virtual environments?**
A: No. PDM can use virtual environments (the default) or PEP 582's `__pypackages__` directory for project-local installs without virtualenv activation.

**Q: Can I migrate from Poetry to PDM?**
A: Yes. PDM can import `pyproject.toml` files from Poetry and convert the metadata to PEP 621 format with `pdm import`.

**Q: Does PDM support monorepos?**
A: Yes. PDM supports workspace-style monorepos with shared lockfiles and cross-project dependencies.

**Q: How does PDM handle Python version management?**
A: PDM detects available Python interpreters and lets you switch with `pdm use`. It does not install Python versions itself—pair it with pyenv or mise for that.

## Sources
- https://github.com/pdm-project/pdm
- https://pdm-project.org

---
Source: https://tokrepo.com/en/workflows/76c003d2-3ba8-11f1-9bc6-00163e2b0d79
Author: Script Depot