pypa-hatch/docs/how-to/environment/dependency-resolution.md

How to configure dependency resolution

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Most Hatch environment types, like the default virtual, simply use pip to install dependencies. Therefore, you can use the standard environment variables that influence pip's behavior.

Here's an example of setting up the default environment to look at 2 private indices (using context formatting for authentication) before finally falling back to PyPI:

[tool.hatch.envs.default.env-vars]
PIP_INDEX_URL = "https://token:{env:GITLAB_API_TOKEN}@gitlab.com/api/v4/groups/<group1_path>/-/packages/pypi/simple/"
PIP_EXTRA_INDEX_URL = "https://token:{env:GITLAB_API_TOKEN}@gitlab.com/api/v4/groups/<group2_path>/-/packages/pypi/simple/ https://pypi.org/simple/"

UV

If you're using UV, a different set of environment variables are available to configure its behavior. The previous example would look like this instead:

[tool.hatch.envs.default.env-vars]
UV_EXTRA_INDEX_URL = "https://token:{env:GITLAB_API_TOKEN}@gitlab.com/api/v4/groups/<group1_path>/-/packages/pypi/simple/"
UV_INDEX_URL = "https://token:{env:GITLAB_API_TOKEN}@gitlab.com/api/v4/groups/<group2_path>/-/packages/pypi/simple/ https://pypi.org/simple/"

!!! tip If you need precise control over the prioritization of package indices, then using UV is recommended because pip has no index order guarantee.