PyPI Protocol

How PyPI dependencies work in Yarn.

The pypi: protocol fetches Python packages from a PyPI-compatible registry and stores the selected wheel in the Yarn cache. It can be used when a project needs to install Python packages alongside its JavaScript dependencies.

{
  "dependencies": {
    "pypi-no-deps": "pypi:1.0.0",
    "pypi-one-dep": "pypi:>=1.0.0,<2.0.0"
  }
}

The range part uses Python package version specifiers. Yarn resolves it against the package metadata, selects the best compatible wheel, and records the exact artifact in the lockfile.

Registry#

By default Yarn queries https://pypi.org. Tests and private deployments may override this endpoint with the ZPM_PYPI_REGISTRY environment variable.

Package names#

The dependency name in your manifest is the package name exposed to the JavaScript project. When needed, you can point it at a different PyPI package name by placing that name after the protocol prefix.

{
  "dependencies": {
    "local-name": "pypi:remote-name@1.0.0"
  }
}