pyproject.toml: Modern Python Dependency Management

pyproject.toml is the contract behind modern Python dependency management. Without it, installers have to execute setup.py or guess build requirements, which leads to fragile builds and non-reproducible environments. This article breaks down the key PEPs (518/517/621) and how pyproject.toml connects to python -m venv + python -m pip for predictable installs. The old problem: executable setup.py Back then, project configuration was executable Python code. Flexible, yes, but it also enabled side e