Skip to content

What is a build frontend?

by Tim Hopper · Markdown
Packaging

A build frontend is a tool that invokes build backends to create Python packages. It manages the build environment and delegates the work of producing artifacts to the backend.

Build frontends in use

  • pip: default package installer; builds packages during installation when no wheel is available
  • build: dedicated PEP 517 builder from PyPA
  • uv: acts as a build frontend via uv build
  • poetry/hatch/pdm: project management tools with build capabilities

What a build frontend handles

  • Discovering and loading the declared build backend
  • Creating an isolated build environment
  • Handling build configuration from pyproject.toml
  • Processing build output (wheels and sdists)
  • Reporting build progress and errors
Build frontends implement PEP 517’s standardized hook API for interacting with backends. Any compliant frontend can invoke any compliant backend.

Running builds

Using the build frontend:

python -m build .             # Build both wheel and sdist
python -m build --wheel .     # Build only wheel
python -m build --sdist .     # Build only sdist

Using uv as a build frontend:

uv build                      # Build both formats
uv build --sdist             # Build only sdist
uv build --wheel             # Build only wheel

Learn More

Last updated on
What is a build backend?What is a lockfile?