uv/docs/concepts/configuration-files.md

Configuration files

uv supports persistent configuration files at both the project- and user-level.

Specifically, uv will search for a pyproject.toml or uv.toml file in the current directory, or in the nearest parent directory.

!!! note

For `tool` commands, which operate at the user level, local configuration
files will be ignored. Instead, uv will exclusively read from user-level configuration
(e.g., `~/.config/uv/uv.toml`) and system-level configuration (e.g., `/etc/uv/uv.toml`).

In workspaces, uv will begin its search at the workspace root, ignoring any configuration defined in workspace members. Since the workspace is locked as a single unit, configuration is shared across all members.

If a pyproject.toml file is found, uv will read configuration from the [tool.uv] table. For example, to set a persistent index URL, add the following to a pyproject.toml:

[[tool.uv.index]]
url = "https://test.pypi.org/simple"
default = true

(If there is no such table, the pyproject.toml file will be ignored, and uv will continue searching in the directory hierarchy.)

uv will also search for uv.toml files, which follow an identical structure, but omit the [tool.uv] prefix. For example:

[[index]]
url = "https://test.pypi.org/simple"
default = true

!!! note

`uv.toml` files take precedence over `pyproject.toml` files, so if both `uv.toml` and
`pyproject.toml` files are present in a directory, configuration will be read from `uv.toml`, and
`[tool.uv]` section in the accompanying `pyproject.toml` will be ignored.

uv will also discover user-level configuration at ~/.config/uv/uv.toml (or $XDG_CONFIG_HOME/uv/uv.toml) on macOS and Linux, or %APPDATA%\uv\uv.toml on Windows; and system-level configuration at /etc/uv/uv.toml (or $XDG_CONFIG_DIRS/uv/uv.toml) on macOS and Linux, or %SYSTEMDRIVE%\ProgramData\uv\uv.toml on Windows.

User-and system-level configuration must use the uv.toml format, rather than the pyproject.toml format, as a pyproject.toml is intended to define a Python project.

If project-, user-, and system-level configuration files are found, the settings will be merged, with project-level configuration taking precedence over the user-level configuration, and user-level configuration taking precedence over the system-level configuration. (If multiple system-level configuration files are found, e.g., at both /etc/uv/uv.toml and $XDG_CONFIG_DIRS/uv/uv.toml, only the first-discovered file will be used, with XDG taking priority.)

For example, if a string, number, or boolean is present in both the project- and user-level configuration tables, the project-level value will be used, and the user-level value will be ignored. If an array is present in both tables, the arrays will be concatenated, with the project-level settings appearing earlier in the merged array.

Settings provided via environment variables take precedence over persistent configuration, and settings provided via the command line take precedence over both.

uv accepts a --no-config command-line argument which, when provided, disables the discovery of any persistent configuration.

uv also accepts a --config-file command-line argument, which accepts a path to a uv.toml to use as the configuration file. When provided, this file will be used in place of any discovered configuration files (e.g., user-level configuration will be ignored).

Settings

See the settings reference for an enumeration of the available settings.

.env

uv run can load environment variables from dotenv files (e.g., .env, .env.local, .env.development), powered by the dotenvy crate.

To load a .env file from a dedicated location, set the UV_ENV_FILE environment variable, or pass the --env-file flag to uv run.

For example, to load environment variables from a .env file in the current working directory:

$ echo "MY_VAR='Hello, world!'" > .env
$ uv run --env-file .env -- python -c 'import os; print(os.getenv("MY_VAR"))'
Hello, world!

The --env-file flag can be provided multiple times, with subsequent files overriding values defined in previous files. To provide multiple files via the UV_ENV_FILE environment variable, separate the paths with a space (e.g., UV_ENV_FILE="/path/to/file1 /path/to/file2").

To disable dotenv loading (e.g., to override UV_ENV_FILE or the --env-file command-line argument), set the UV_NO_ENV_FILE environment variable to 1, or pass the--no-env-file flag to uv run.

If the same variable is defined in the environment and in a .env file, the value from the environment will take precedence.

Configuring the pip interface

A dedicated [tool.uv.pip] section is provided for configuring just the uv pip command line interface. Settings in this section will not apply to uv commands outside the uv pip namespace. However, many of the settings in this section have corollaries in the top-level namespace which do apply to the uv pip interface unless they are overridden by a value in the uv.pip section.

The uv.pip settings are designed to adhere closely to pip's interface and are declared separately to retain compatibility while allowing the global settings to use alternate designs (e.g., --no-build).

As an example, setting the index-url under [tool.uv.pip], as in the following pyproject.toml, would only affect the uv pip subcommands (e.g., uv pip install, but not uv sync, uv lock, or uv run):

[tool.uv.pip]
index-url = "https://test.pypi.org/simple"