As is this might not be clear. What I'm trying to convey is that you do

pixi init example && cd example pixi add numpy pixi add --pypi scipy 

generating

[workspace] channels = ["conda-forge"] name = "example" platforms = ["linux-64"] version = "0.1.0" [tasks] [dependencies] numpy = ">=2.3.4,<3" [pypi-dependencies] scipy = ">=1.16.3, <2"

Pixi will get only scipy from PyPI and will use everything else from conda-forge

$ pixi list | grep 'numpy\|scipy' numpy 2.3.4 py314h2b28147_0 8.5 MiB conda https://conda.anaconda.org/conda-forge/ scipy 1.16.3 112.9 MiB pypi scipy-1.16.3-cp314-cp314-manylinux2014_x86_64.manylinux_2_17_x86_64.whl

To be clear, that is the same behavior as

conda create --name debug --yes --channel conda-forge numpy pip conda activate debug pip install scipy 

though it is explicitly understood that Pixi will handle the resolution to use conda packages where it can, and the behavior is fully described in the manifest file and lock file, so there is no ambiguity of how a conda vs. Python package dependency might get resolved at install time.

Originally posted by @matthewfeickert in #587 (comment)