pyproject.toml

The pyproject.toml file is the standard configuration file for modern Python projects, defined by PEP 518. It serves as a central place to specify project metadata, dependencies, build requirements, and tool configurations.

Key Aspects

• Single Source: Consolidates project configuration that was historically spread across multiple files like setup.py, setup.cfg, and requirements.txt
• Standards Compliant: Follows modern Python packaging standards (PEP 517/518/621)
• Tool Agnostic: Works with any compliant build backend or package manager
• TOML Format: Uses TOML for improved readability and reduced syntax errors compared to JSON or INI formats

Core Sections Examples

Project Metadata (PEP 621)

[project]
name = "example"
version = "0.1.0"
description = "A example project"
requires-python = ">=3.8"
dependencies = [
    "requests>=2.28.0",
    "pandas~=2.0.0",
]

Build System (PEP 517)

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

Tool Configuration

[tool.uv]
dependencies = ["pytest>=7.0.0"]

[tool.ruff]
line-length = 88

Important Fields

Learn More

• Python Packaging User Guide
• PEP 518 - Build System Requirements
• PEP 621 - Project Metadata
• TOML Documentation