uv/docs/concepts/preview.md
Zanie Blue 709e0ba238 Remove the native system store from the keyring providers (#15612)
We're not sure what the best way to expose the native store to users is
yet and it's a bit weird that you can use this in the `uv auth` commands
but can't use any of the other keyring provider options. The simplest
path forward is to just not expose it to users as a keyring provider,
and instead frame it as a preview alternative to the plaintext uv
credentials store. We can revisit the best way to expose configuration
before stabilization.

Note this pull request retains the _internal_ keyring provider
implementation — we can refactor it out later but I wanted to avoid a
bunch of churn here.
2025-09-02 13:16:52 -05:00

2.7 KiB

Preview features

uv includes opt-in preview features to provide an opportunity for community feedback and increase confidence that changes are a net-benefit before enabling them for everyone.

Enabling preview features

To enable all preview features, use the --preview flag:

$ uv run --preview ...

Or, set the UV_PREVIEW environment variable:

$ UV_PREVIEW=1 uv run ...

To enable specific preview features, use the --preview-features flag:

$ uv run --preview-features foo ...

The --preview-features flag can be repeated to enable multiple features:

$ uv run --preview-features foo --preview-features bar ...

Or, features can be provided in a comma separated list:

$ uv run --preview-features foo,bar ...

The UV_PREVIEW_FEATURES environment variable can be used similarly, e.g.:

$ UV_PREVIEW_FEATURES=foo,bar uv run ...

For backwards compatibility, enabling preview features that do not exist will warn, but not error.

Using preview features

Often, preview features can be used without changing any preview settings if the behavior change is gated by some sort of user interaction, For example, while pylock.toml support is in preview, you can use uv pip install with a pylock.toml file without additional configuration because specifying the pylock.toml file indicates you want to use the feature. However, a warning will be displayed that the feature is in preview. The preview feature can be enabled to silence the warning.

Other preview features change behavior without changes to your use of uv. For example, when the python-upgrade feature is enabled, the default behavior of uv python install changes to allow uv to upgrade Python versions transparently. This feature requires enabling the preview flag for proper usage.

Available preview features

The following preview features are available:

Disabling preview features

The --no-preview option can be used to disable preview features.