.. highlight:: none

.. _python.org/downloads: https://www.python.org/downloads/

.. _Microsoft Store app: https://apps.microsoft.com/detail/9NQ7512CXL7T

.. _legacy launcher: https://www.python.org/ftp/python/3.14.0/win32/launcher.msi

.. _using-on-windows:

*************************

Using Python on Windows

*************************

This document aims to give an overview of Windows-specific behaviour you should

know about when using Python on Microsoft Windows.

Unlike most Unix systems and services, Windows does not include a system

supported installation of Python. Instead, Python can be obtained from a number

of distributors, including directly from the CPython team. Each Python

distribution will have its own benefits and drawbacks, however, consistency with

other tools you are using is generally a worthwhile benefit. Before committing

to the process described here, we recommend investigating your existing tools to

see if they can provide Python directly.

To obtain Python from the CPython team, use the Python install manager. This

is a standalone tool that makes Python available as global commands on your

Windows machine, integrates with the system, and supports updates over time. You

can download the Python install manager from `python.org/downloads`_ or through

the `Microsoft Store app`_.

Once you have installed the Python install manager, the global ``python``

command can be used from any terminal to launch your current latest version of

Python. This version may change over time as you add or remove different

versions, and the ``py list`` command will show which is current.

In general, we recommend that you create a :ref:`virtual environment <tut-venv>`

for each project and run ``<env>\Scripts\Activate`` in your terminal to use it.

This provides isolation between projects, consistency over time, and ensures

that additional commands added by packages are also available in your session.

Create a virtual environment using ``python -m venv <env path>``.

If the ``python`` or ``py`` commands do not seem to be working, see the

:ref:`Troubleshooting <pymanager-troubleshoot>` section below. There are

sometimes additional manual steps required to configure your PC.

Apart from using the Python install manager, Python can also be obtained as

NuGet packages. See :ref:`windows-nuget` below for more information on these

packages.

The embeddable distros are minimal packages of Python suitable for embedding

into larger applications. They can be installed using the Python install

manager. See :ref:`windows-embeddable` below for more information on these

packages.

.. _pymanager:

.. _windows-store:

.. _setting-envvars:

.. _windows-path-mod:

.. _launcher:

Python install manager

======================

Installation

------------

The Python install manager can be installed from the `Microsoft Store app`_

or downloaded and installed from `python.org/downloads`_. The two versions are

identical.

To install through the Store, simply click "Install". After it has completed,

open a terminal and type ``python`` to get started.

To install the file downloaded from python.org, either double-click and select

"Install", or run ``Add-AppxPackage <path to MSIX>`` in Windows PowerShell.

After installation, the ``python``, ``py``, and ``pymanager`` commands should be

available. If you have existing installations of Python, or you have modified

your :envvar:`PATH` variable, you may need to remove them or undo the

modifications. See :ref:`pymanager-troubleshoot` for more help with fixing

non-working commands.

When you first install a runtime, you will likely be prompted to add a directory

to your :envvar:`PATH`. This is optional, if you prefer to use the ``py``

command, but is offered for those who prefer the full range of aliases (such

as |python_x_dot_y_exe_literal|) to be available. The directory will be

:file:`%LocalAppData%\\Python\\bin` by default, but may be customized by an

administrator. Click Start and search for "Edit environment variables for your

account" for the system settings page to add the path.

Each Python runtime you install will have its own directory for scripts. These

also need to be added to :envvar:`PATH` if you want to use them.

The Python install manager will be automatically updated to new releases. This

does not affect any installs of Python runtimes. Uninstalling the Python install

manager does not uninstall any Python runtimes.

If you are not able to install an MSIX in your context, for example, you are

using automated deployment software that does not support it, or are targeting

Windows Server 2019, see :ref:`pymanager-advancedinstall` below for more

information.

Basic use

---------

The recommended command for launching Python is ``python``, which will either

launch the version requested by the script being launched, an active virtual

environment, or the default installed version, which will be the latest stable

release unless configured otherwise. If no version is specifically requested and

no runtimes are installed at all, the current latest release will be installed

automatically.

For all scenarios involving multiple runtime versions, the recommended command

is ``py``. This may be used anywhere in place of ``python`` or the older

``py.exe`` launcher. By default, ``py`` matches the behaviour of ``python``, but

also allows command line options to select a specific version as well as

subcommands to manage installations. These are detailed below.

Because the ``py`` command may already be taken by the previous version, there

is also an unambiguous ``pymanager`` command. Scripted installs that are

intending to use Python install manager should consider using ``pymanager``, due

to the lower chance of encountering a conflict with existing installs. The only

difference between the two commands is when running without any arguments:

``py`` will launch your default interpreter, while ``pymanager`` will display

help (``pymanager exec ...`` provides equivalent behaviour to ``py ...``).

Each of these commands also has a windowed version that avoids creating a

console window. These are ``pyw``, ``pythonw`` and ``pywmanager``. A ``python3``

command is also included that mimics the ``python`` command. It is intended to

catch accidental uses of the typical POSIX command on Windows, but is not meant

to be widely used or recommended.

To launch your default runtime, run ``python`` or ``py`` with the arguments you

want to be passed to the runtime (such as script files or the module to launch):

.. code::

$> py

...

$> python my-script.py

...

$> py -m this

...

The default runtime can be overridden with the :envvar:`PYTHON_MANAGER_DEFAULT`

environment variable, or a configuration file. See :ref:`pymanager-config` for

information about configuration settings.

To launch a specific runtime, the ``py`` command accepts a ``-V:<TAG>`` option.

This option must be specified before any others. The tag is part or all of the

identifier for the runtime; for those from the CPython team, it looks like the

version, potentially with the platform. For compatibility, the ``V:`` may be

omitted in cases where the tag refers to an official release and starts with

``3``.

.. parsed-literal::

$> py -V:|version| ...

$> py -V:3-arm64 ...

Runtimes from other distributors may require the *company* to be included as

well.

It should be separated from the tag by a slash (either ``/`` or ``\``),

and may be shortened to any prefix of its full value.

Specifying the company is optional when it is ``PythonCore``, and specifying the

tag is optional (but not the slash) when you want the latest release from a

specific company.

.. code::

$> py -V:Distributor\1.0 ...

$> py -V:distrib/ ...

If no version is specified, but a script file is passed, the script will be

inspected for a *shebang line*. This is a special format for the first line in

a file that allows overriding the command. See :ref:`pymanager-shebang` for more

information. When there is no shebang line, or it cannot be resolved, the script

will be launched with the default runtime.

If you are running in an active virtual environment, have not requested a

particular version, and there is no shebang line, the default runtime will be

that virtual environment. In this scenario, the ``python`` command was likely

already overridden and none of these checks occurred. However, this behaviour

ensures that the ``py`` command can be used interchangeably.

When no runtimes are installed, any launch command will try to install the

requested version and launch it. However, after any version is installed, only

the ``py exec ...`` and ``pymanager exec ...`` commands will install if the

requested version is absent. Other forms of commands will display an error and

direct you to use ``py install`` first.

Command help

------------

The ``py help`` command will display the full list of supported commands, along

with their options. Any command may be passed the ``-?`` option to display its

help, or its name passed to ``py help``.

.. code::

$> py help

$> py help install

$> py install /?

All commands support some common options, which will be shown by ``py help``.

These options must be specified after any subcommand. Specifying ``-v`` or

``--verbose`` will increase the amount of output shown, and ``-vv`` will

increase it further for debugging purposes. Passing ``-q`` or ``--quiet`` will

reduce output, and ``-qq`` will reduce it further.

The ``--config=<PATH>`` option allows specifying a configuration file to

override multiple settings at once. See :ref:`pymanager-config` below for more

information about these files.

Listing runtimes

----------------

.. code::

$> py list [-f=|--format=<FMT>] [-1|--one] [--online|-s=|--source=<URL>] [<TAG>...]

The list of installed runtimes can be seen using ``py list``. A filter may be

added in the form of one or more tags (with or without company specifier), and

each may include a ``<``, ``<=``, ``>=`` or ``>`` prefix to restrict to a range.

A range of formats are supported, and can be passed as the ``--format=<FMT>`` or

``-f <FMT>`` option. Formats include ``table`` (a user-friendly table view),

``csv`` (comma-separated table), ``json`` (a single JSON blob), ``jsonl`` (one

JSON blob per result), ``exe`` (just the executable path), ``prefix`` (just the

prefix path).

The ``--one`` or ``-1`` option only displays a single result. If the default

runtime is included, it will be the one. Otherwise, the "best" result is shown

("best" is deliberately vaguely defined, but will usually be the most recent

version). The result shown by ``py list --one <TAG>`` will match the runtime

that would be launched by ``py -V:<TAG>``.

The ``--only-managed`` option excludes results that were not installed by the

Python install manager. This is useful when determining which runtimes may be

updated or uninstalled through the ``py`` command.

The ``--online`` option is short for passing ``--source=<URL>`` with the default

source. Passing either of these options will search the online index for

runtimes that can be installed. The result shown by ``py list --online --one

<TAG>`` will match the runtime that would be installed by ``py install <TAG>``.

.. parsed-literal::

$> py list --online |version|

For compatibility with the old launcher, the ``--list``, ``--list-paths``,

``-0`` and ``-0p`` commands (for example, ``py -0p``) are retained. They do not allow

additional options, and will produce legacy-formatted output.

Installing runtimes

-------------------

.. code::

$> py install [-s=|--source=<URL>] [-f|--force] [-u|--update] [--dry-run] [<TAG>...]

New runtime versions may be added using ``py install``. One or more tags may be

specified, and the special tag ``default`` may be used to select the default.

Ranges are not supported for installation.

CPython publishes multiple runtime variants. For most users,

``PythonCore`` is recommended and provides the standard CPython runtime.

Tags without any prefix are treated as ``PythonCore\<TAG>``.

``PythonTest`` includes the standard runtime together with the test suite

and debugging symbols. It is intended for contributors or users who need

these additional files for testing or debugging Python.

``PythonEmbed`` provides a minimal embeddable distribution for

applications that bundle Python rather than for interactive use. It

would normally be used with the ``--target`` option described below.

To see the available runtime variants, run::

py list --online

To install a specific variant, include it in the tag passed to

``py install``:

.. parsed-literal::

py install PythonTest\\\ |version|

The ``--source=<URL>`` option allows overriding the online index that is used to

obtain runtimes. This may be used with an offline index, as shown in

:ref:`pymanager-offline`.

Passing ``--force`` will ignore any cached files and remove any existing install

to replace it with the specified one.

Passing ``--update`` will replace existing installs if the new version is newer.

Otherwise, they will be left. If no tags are provided with ``--update``, all

installs managed by the Python install manager will be updated if newer versions

are available. Updates will remove any modifications made to the install,

including globally installed packages, but will leave ``site-packages`` and

``Scripts`` directories as is. Virtual environments are also unaffected.

Passing ``--dry-run`` will generate output and logs, but will not modify any

installs.

Passing ``--refresh`` will update all registrations for installed runtimes. This

will recreate Start menu shortcuts, registry keys, and global aliases (such as

|python_x_dot_y_exe_literal| or for any installed scripts). These are automatically

refreshed on installation of any runtime, but may need to be manually refreshed

after installing packages.

In addition to the above options, the ``--target`` option will extract the

runtime to the specified directory instead of doing a normal install.

This is useful for embedding runtimes into larger applications.

Unlike a normal install, ``py`` will not be aware of the extracted runtime,

and no Start menu or other shortcuts will be created.

To launch the runtime, directly execute the main executable (typically

``python.exe``) in the target directory.

.. code::

$> py install ... [-t=|--target=<PATH>] <TAG>

The ``py exec`` command will install the requested runtime if it is not already

present. This is controlled by the ``automatic_install`` configuration

(:envvar:`PYTHON_MANAGER_AUTOMATIC_INSTALL`), and is enabled by default.

If no runtimes are available at all, all launch commands will do an automatic

install if the configuration setting allows. This is to ensure a good experience

for new users, but should not generally be relied on rather than using the

``py exec`` command or explicit install commands.

.. _pymanager-offline:

Offline installs

----------------

To perform offline installs of Python, you will need to first create an offline

index on a machine that has network access.

.. code::

$> py install --download=<PATH> ... <TAG>...

The ``--download=<PATH>`` option will download the packages for the listed tags

and create a directory containing them and an ``index.json`` file suitable for

later installation. This entire directory can be moved to the offline machine

and used to install one or more of the bundled runtimes:

.. code::

$> py install --source="<PATH>\index.json" <TAG>...

The Python install manager can be installed by downloading its installer and

moving it to another machine before installing.

Alternatively, the ZIP files in an offline index directory can simply be

transferred to another machine and extracted. This will not register the install

in any way, and so it must be launched by directly referencing the executables

in the extracted directory, but it is sometimes a preferable approach in cases

where installing the Python install manager is not possible or convenient.

In this way, Python runtimes can be installed and managed on a machine without

access to the internet.

Uninstalling runtimes

---------------------

.. code::

$> py uninstall [-y|--yes] <TAG>...

Runtimes may be removed using the ``py uninstall`` command. One or more tags

must be specified. Ranges are not supported here.

The ``--yes`` option bypasses the confirmation prompt before uninstalling.

Instead of passing tags individually, the ``--purge`` option may be specified.

This will remove all runtimes managed by the Python install manager, including

cleaning up the Start menu, registry, and any download caches. Runtimes that

were not installed by the Python install manager will not be impacted, and

neither will manually created configuration files.

.. code::

$> py uninstall [-y|--yes] --purge

The Python install manager can be uninstalled through the Windows "Installed

apps" settings page. This does not remove any runtimes, and they will still be

usable, though the global ``python`` and ``py`` commands will be removed.

Reinstalling the Python install manager will allow you to manage these runtimes

again. To completely clean up all Python runtimes, run with ``--purge`` before

uninstalling the Python install manager.

.. _pymanager-config:

Configuration

-------------

Python install manager is configured with a hierarchy of configuration files,

environment variables, command-line options, and registry settings. In general,

configuration files have the ability to configure everything, including the

location of other configuration files, while registry settings are

administrator-only and will override configuration files. Command-line options

override all other settings, but not every option is available.

This section will describe the defaults, but be aware that modified or

overridden installs may resolve settings differently.

A global configuration file may be configured by an

:ref:`administrator <pymanager-admin-config>`

and would be read first. The user configuration file is stored at

:file:`%AppData%\\Python\\pymanager.json`

(note that this location is under ``Roaming``, not ``Local``) and is read next,

overwriting any settings from earlier files. An additional configuration file

may be specified as the ``PYTHON_MANAGER_CONFIG`` environment variable or the

``--config`` command line option (but not both).

These locations may be modified by administrative customization options listed

later.

The following settings are those that are considered likely to be modified in

normal use. Later sections list those that are intended for administrative

customization.

.. Sphinx bug with text writer; remove widths & caption temporarily

.. :widths: 2, 2, 4

.. rubric:: Standard configuration options

.. list-table::

:header-rows: 1

* - Config Key

- Environment Variable

- Description

* - ``default_tag``

- .. envvar:: PYTHON_MANAGER_DEFAULT

- The preferred default version to launch or install.

By default, this is interpreted as the most recent non-prerelease version

from the CPython team.

* - ``default_platform``

- ``PYTHON_MANAGER_DEFAULT_PLATFORM``

- The preferred default platform to launch or install.

This is treated as a suffix to the specified tag, such that |py_v_x_dot_y_literal|

would prefer an install for |x_dot_y_64_literal| if it exists

(and ``default_platform`` is ``-64``),

but will use |x_dot_y_literal| if no tagged install exists.

* - ``logs_dir``

- ``PYTHON_MANAGER_LOGS``

- The location where log files are written.

By default, :file:`%TEMP%`.

* - ``automatic_install``

- .. envvar:: PYTHON_MANAGER_AUTOMATIC_INSTALL

- True to allow automatic installs when using ``py exec`` to launch (or

``py`` when no runtimes are installed yet).

Other commands will not automatically install, regardless of this

setting.

By default, true.

* - ``include_unmanaged``

- ``PYTHON_MANAGER_INCLUDE_UNMANAGED``

- True to allow listing and launching runtimes that were not installed

by the Python install manager, or false to exclude them.

By default, true.

* - ``shebang_can_run_anything``

- ``PYTHON_MANAGER_SHEBANG_CAN_RUN_ANYTHING``

- True to allow shebangs in ``.py`` files to launch applications other than

Python runtimes, or false to prevent it.

By default, true.

* - ``shebang_templates``

- (none)

- Mapping from shebang line template to alternative command, such as

``py -V:<tag>`` or a substitute string.

See :ref:`pymanager-shebang` for more details.

* - ``log_level``

- ``PYMANAGER_VERBOSE``, ``PYMANAGER_DEBUG``

- Set the default level of output (0-50).

By default, 20.

Lower values produce more output.

The environment variables are boolean, and may produce additional

output during startup that is later suppressed by other configuration.

* - ``confirm``

- ``PYTHON_MANAGER_CONFIRM``

- True to confirm certain actions before taking them (such as uninstall),

or false to skip the confirmation.

By default, true.

* - ``install.source``

- ``PYTHON_MANAGER_SOURCE_URL``

- Override the index feed to obtain new installs from.

* - ``install.enable_entrypoints``

- (none)

- True to generate global commands for installed packages (such as

``pip.exe``). These are defined by the packages themselves.

If set to false, only the Python interpreter has global commands created.

By default, true. You should run ``py install --refresh`` after changing

this setting.

* - ``list.format``

- ``PYTHON_MANAGER_LIST_FORMAT``

- Specify the default format used by the ``py list`` command.

By default, ``table``.

* - ``install_dir``

- (none)

- Specify the root directory that runtimes will be installed into.

If you change this setting, previously installed runtimes will not be

usable unless you move them to the new location.

* - ``global_dir``

- (none)

- Specify the directory where global commands (such as |python_x_dot_y_exe_literal|

and ``pip.exe``) are stored.

This directory should be added to your :envvar:`PATH` to make the

commands available from your terminal.

* - ``download_dir``

- (none)

- Specify the directory where downloaded files are stored.

This directory is a temporary cache, and can be cleaned up from time to

time.

Dotted names should be nested inside JSON objects, for example, ``list.format``

would be specified as ``{"list": {"format": "table"}}``.

.. _pymanager-shebang:

Shebang lines

-------------

If the first line of a script file starts with ``#!``, it is known as a

"shebang" line. Linux and other Unix-like operating systems have native

support for such lines and they are commonly used on such systems to indicate

how a script should be executed. The ``python`` and ``py`` commands allow the

same facilities to be used with Python scripts on Windows.

To allow shebang lines in Python scripts to be portable between Unix and

Windows, a number of 'virtual' commands are supported to specify which

interpreter to use. The supported virtual commands are:

* ``/usr/bin/env <ALIAS>``

* ``/usr/bin/env -S <ALIAS>``

* ``/usr/bin/<ALIAS>``

* ``/usr/local/bin/<ALIAS>``

* ``<ALIAS>``

For example, if the first line of your script starts with

.. code-block:: sh

#! /usr/bin/python

The default Python or an active virtual environment will be located and used.

As many Python scripts written to work on Unix will already have this line,

you should find these scripts can be used by the launcher without modification.

If you are writing a new script on Windows which you hope will be useful on

Unix, you should use one of the shebang lines starting with ``/usr``.

Any of the above virtual commands can have ``<ALIAS>`` replaced by an alias from

an installed runtime. That is, any command generated in the global aliases

directory (which you may have added to your :envvar:`PATH` environment variable)

can be used in a shebang, even if it is not on your :envvar:`PATH`. This allows

the use of shebangs like ``/usr/bin/python3.12`` to select a particular runtime.

If no runtimes are installed, or if automatic installation is enabled, the

requested runtime will be installed if necessary. See :ref:`pymanager-config`

for information about configuration settings.

The ``/usr/bin/env`` form of shebang line will also search the :envvar:`PATH`

environment variable for unrecognized commands. This corresponds to the

behaviour of the Unix ``env`` program, which performs the same search, but

prefers launching known Python commands. A warning may be displayed when

searching for arbitrary executables, and this search may be disabled by the

``shebang_can_run_anything`` configuration option.

Shebang lines that do not match any of the patterns are treated as *Windows*

executable paths that are absolute or relative to the directory containing the

script file. This is a convenience for Windows-only scripts, such as those

generated by an installer, since the behavior is not compatible with Unix-style

shells. These paths may be quoted, and may include multiple arguments, after

which the path to the script and any additional arguments will be appended.

This functionality may be disabled by the ``shebang_can_run_anything``

configuration option.

Since version 26.3 of the Python install manager, custom shebang templates may

be added to your configuration file. Add the ``shebang_templates`` object with

one member for each template (the string to match) and the command to use when

the template is matched. Most commands should be ``py -V:<tag>`` (or ``pyw``) to

launch one of your installed runtimes. The ``py -3.<version>`` form is also

allowed, as is a plain ``py`` to launch the default. No other arguments are

supported.

.. code:: json5

{

"shebang_templates": {

"/usr/bin/python": "py",

"/usr/bin/my_custom_python": "py -V:MyCustomPython/3"

}

}

If the substitute command is not ``py`` or ``pyw``, it will be written back into

the shebang and regular handling continues. If launching arbitrary executables

is permitted, then providing a full path will allow you to redirect from Python

to any executable. The template should match either the entire line (ignoring

leading and trailing whitespace), or up to the first space in the shebang line.

.. note::

The behaviour of shebangs in the Python install manager is subtly different

from the previous ``py.exe`` launcher, and the old configuration options no

longer apply. If you are specifically reliant on the old behaviour or

configuration, we recommend installing the `legacy launcher`_. The legacy

launcher's ``py`` command will override PyManager's one by default, and you

will need to use ``pymanager`` commands for installing and uninstalling.

.. _Add-AppxPackage: https://learn.microsoft.com/powershell/module/appx/add-appxpackage

.. _Remove-AppxPackage: https://learn.microsoft.com/powershell/module/appx/remove-appxpackage

.. _Add-AppxProvisionedPackage: https://learn.microsoft.com/powershell/module/dism/add-appxprovisionedpackage

.. _PackageManager: https://learn.microsoft.com/uwp/api/windows.management.deployment.packagemanager

.. _pymanager-advancedinstall:

Advanced installation

---------------------

For situations where an MSIX cannot be installed, such as some older

administrative distribution platforms, there is an MSI available from the

python.org downloads page. This MSI has no user interface, and can only perform

per-machine installs to its default location in Program Files. It will attempt

to modify the system :envvar:`PATH` environment variable to include this install

location, but be sure to validate this on your configuration.

.. note::

Windows Server 2019 is the only version of Windows that CPython supports that

does not support MSIX. For Windows Server 2019, you should use the MSI.

Be aware that the MSI package does not bundle any runtimes, and so is not

suitable for installs into offline environments without also creating an offline

install index. See :ref:`pymanager-offline` and :ref:`pymanager-admin-config`

for information on handling these scenarios.

Runtimes installed by the MSI are shared with those installed by the MSIX, and

are all per-user only. The Python install manager does not support installing

runtimes per-machine. To emulate a per-machine install, you can use ``py install

--target=<shared location>`` as administrator and add your own system-wide

modifications to :envvar:`PATH`, the registry, or the Start menu.

When the MSIX is installed, but commands are not available in the :envvar:`PATH`

environment variable, they can be found under

:file:`%LocalAppData%\\Microsoft\\WindowsApps\\PythonSoftwareFoundation.PythonManager_3847v3x7pw1km`

or

:file:`%LocalAppData%\\Microsoft\\WindowsApps\\PythonSoftwareFoundation.PythonManager_qbz5n2kfra8p0`,

depending on whether it was installed from python.org or through the Windows

Store. Attempting to run the executable directly from Program Files is not

recommended.

To programmatically install the Python install manager, it is easiest to use

WinGet, which is included with all supported versions of Windows:

.. code-block:: powershell

$> winget install 9NQ7512CXL7T -e --accept-package-agreements --disable-interactivity

# Optionally run the configuration checker and accept all changes

$> py install --configure -y

To download the Python install manager and install on another machine, the

following WinGet command will download the required files from the Store to your

Downloads directory (add ``-d <location>`` to customize the output location).

This also generates a YAML file that appears to be unnecessary, as the

downloaded MSIX can be installed by launching or using the commands below.

.. code-block:: powershell

$> winget download 9NQ7512CXL7T -e --skip-license --accept-package-agreements --accept-source-agreements

To programmatically install or uninstall an MSIX using only PowerShell, the

`Add-AppxPackage`_ and `Remove-AppxPackage`_ PowerShell cmdlets are recommended:

.. code-block:: powershell

$> Add-AppxPackage C:\Downloads\python-manager-25.0.msix

...

$> Get-AppxPackage PythonSoftwareFoundation.PythonManager | Remove-AppxPackage

The latest release can be downloaded and installed by Windows by passing the

AppInstaller file to the Add-AppxPackage command. This installs using the MSIX

on python.org, and is only recommended for cases where installing via the Store

(interactively or using WinGet) is not possible.

.. code-block:: powershell

$> Add-AppxPackage -AppInstallerFile https://www.python.org/ftp/python/pymanager/pymanager.appinstaller

Other tools and APIs may also be used to provision an MSIX package for all users

on a machine, but Python does not consider this a supported scenario. We suggest

looking into the PowerShell `Add-AppxProvisionedPackage`_ cmdlet, the native

Windows `PackageManager`_ class, or the documentation and support for your

deployment tool.

Regardless of the install method, users will still need to install their own

copies of Python itself, as there is no way to trigger those installs without

being a logged-in user. When using the MSIX, the latest version of Python will

be available for all users to install without network access.

Note that the MSIX downloadable from the Store and from the Python website are

subtly different and cannot be installed at the same time. Wherever possible,

we suggest using the above WinGet commands to download the package from the

Store to reduce the risk of setting up conflicting installs. There are no

licensing restrictions on the Python install manager that would prevent using

the Store package in this way.

.. _pymanager-admin-config:

Administrative configuration

----------------------------

There are a number of options that may be useful for administrators to override

configuration of the Python install manager. These can be used to provide local

caching, disable certain shortcut types, override bundled content. All of the

above configuration options may be set, as well as those below.

Configuration options may be overridden in the registry by setting values under

:file:`HKEY_LOCAL_MACHINE\\Software\\Policies\\Python\\PyManager`, where the

value name matches the configuration key and the value type is ``REG_SZ``. Note

that this key can itself be customized, but only by modifying the core config

file distributed with the Python install manager. We recommend, however, that

registry values are used only to set ``base_config`` to a JSON file containing

the full set of overrides. Registry key overrides will replace any other

configured setting, while ``base_config`` allows users to further modify

settings they may need.

Note that most settings with environment variables support those variables

because their default setting specifies the variable. If you override them, the

environment variable will no longer work, unless you override it with another

one. For example, the default value of ``confirm`` is literally

``%PYTHON_MANAGER_CONFIRM%``, which will resolve the variable at load time. If

you override the value to ``yes``, then the environment variable will no longer

be used. If you override the value to ``%CONFIRM%``, then that environment

variable will be used instead.

Configuration settings that are paths are interpreted as relative to the

directory containing the configuration file that specified them.

.. Sphinx bug with text writer; remove widths & caption temporarily

.. :widths: 1, 4

.. rubric:: Administrative configuration options

.. list-table::

:header-rows: 1

* - Config Key

- Description

* - ``base_config``

- The highest priority configuration file to read.

Note that only the built-in configuration file and the registry can

modify this setting.

* - ``user_config``

- The second configuration file to read.

* - ``additional_config``

- The third configuration file to read.

* - ``registry_override_key``

- Registry location to check for overrides.

Note that only the built-in configuration file can modify this setting.

* - ``bundled_dir``

- Read-only directory containing locally cached files.

* - ``install.fallback_source``

- Path or URL to an index to consult when the main index cannot be accessed.

* - ``install.enable_shortcut_kinds``

- Comma-separated list of shortcut kinds to allow

(for example, ``"pep514,start"``).

Enabled shortcuts may still be disabled by ``disable_shortcut_kinds``.

* - ``install.disable_shortcut_kinds``

- Comma-separated list of shortcut kinds to exclude

(for example, ``"pep514,start"``).

Disabled shortcuts are not reactivated by ``enable_shortcut_kinds``.

* - ``install.hard_link_entrypoints``

- True to use hard links for global shortcuts to save disk space. If false,

each shortcut executable is copied instead. After changing this setting,

you must run ``py install --refresh --force`` to update existing

commands.

By default, true. Disabling this may be necessary for troubleshooting or

systems that have issues with file links.

* - ``pep514_root``

- Registry location to read and write PEP 514 entries into.

By default, :file:`HKEY_CURRENT_USER\\Software\\Python`.

* - ``start_folder``

- Start menu folder to write shortcuts into.

By default, ``Python``.

This path is relative to the user's Programs folder.

* - ``virtual_env``

- Path to the active virtual environment.

By default, this is ``%VIRTUAL_ENV%``, but may be set empty

to disable venv detection.

* - ``shebang_can_run_anything_silently``

- True to suppress visible warnings when a shebang launches an application

other than a Python runtime.

* - ``source_settings``

- A mapping from source URL to settings specific to that index.

When multiple configuration files include this section, URL settings are

added or overwritten, but individual settings are not merged.

These settings are currently only for :ref:`index signatures

<pymanager-index-signatures>`.

.. _install-freethreaded-windows:

Installing free-threaded binaries

---------------------------------

.. versionadded:: 3.13

Pre-built distributions of the free-threaded build are available

by installing tags with the ``t`` suffix.

.. parsed-literal::

$> py install |version|\ t

$> py install |version|\ t-arm64

$> py install |version|\ t-32

This will install and register as normal. If you have no other runtimes

installed, then ``python`` will launch this one. Otherwise, you will need to use

|py_v_x_dot_y_t_literal| or, if you have added the global aliases directory to your

:envvar:`PATH` environment variable, the |python_x_dot_y_t_exe_literal| commands.

.. _pymanager-index-signatures:

Index signatures

----------------

.. versionadded:: 26.2

Index files may be signed to detect tampering. A signature is a catalog file

at the same URL as the index with ``.cat`` added to the filename. The catalog

file should contain the hash of its matching index file, and should be signed

with a valid Authenticode signature. This allows standard tooling (on Windows)

to generate a signature, and any certificate may be used as long as the client

operating system already trusts its certification authority (root CA).

Index signatures are only downloaded and checked when the local configuration's

``source_settings`` section includes the index URL and ``requires_signature`` is

true, or the index JSON contains ``requires_signature`` set to true. When the

setting exists in local configuration, even when false, settings in the index

are ignored.

As well as requiring a valid signature, the ``required_root_subject`` and

``required_publisher_subject`` settings can further restrict acceptable

signatures based on the certificate Subject fields. Any attribute specified in

the configuration must match the attribute in the certificate (additional

attributes in the certificate are ignored). Typical attributes are ``CN=`` for

the common name, ``O=`` for the organization, and ``C=`` for the

publisher's country.

Finally, the ``required_publisher_eku`` setting allows requiring that a specific

Enhanced Key Usage (EKU) has been assigned to the publisher certificate. For

example, the EKU ``1.3.6.1.5.5.7.3.3`` indicates that the certificate was

intended for code signing (as opposed to server or client authentication).

In combination with a specific root CA, this provides another mechanism to

verify a legitimate signature.

This is an example ``source_settings`` section from a configuration file. In

this case, the publisher of the feed is uniquely identified by the combination

of the Microsoft Identity Verification root and the EKU assigned by that root.

The signature for this case would be found at

``https://www.python.org/ftp/python/index-windows.json.cat``.

.. code:: json5

{

"source_settings": {

"https://www.python.org/ftp/python/index-windows.json": {

"requires_signature": true,

"required_root_subject": "CN=Microsoft Identity Verification Root Certificate Authority 2020",

"required_publisher_subject": "CN=Python Software Foundation",

"required_publisher_eku": "1.3.6.1.4.1.311.97.608394634.79987812.305991749.578777327"

}

}

}

The same settings could be specified in the ``index.json`` file instead. In this

case, the root and EKU are omitted, meaning that the signature must be valid and

have a specific common name in the publisher's certificate, but no other checks

are used.

.. code:: json5

{

"requires_signature": true,

"required_publisher_subject": "CN=Python Software Foundation",

"versions": [

// ...

]

}

When settings from inside a feed are used, the user is notified and the settings

are shown in the log file or verbose output. It is recommended to copy these

settings into a local configuration file for feeds that will be used frequently,

so that unauthorised modifications to the feed cannot disable verification.

It is not possible to override the location of the signature file in the feed or

through a configuration file. Administrators can provide their own

``source_settings`` in a mandatory configuration file (see

:ref:`pymanager-admin-config`).

If signature validation fails, you will be notified and prompted to continue.

When interactive confirmation is not allowed (for example, because ``--yes`` was

specified), it will always abort. To use a feed with invalid configuration in

this scenario, you must provide a configuration file that disables signature

checking for that feed.

.. code:: json5

"source_settings": {

"https://www.example.com/feed-with-invalid-signature.json": {

"requires_signature": false

}

}

Proxy settings

--------------

.. versionadded:: 26.4

By default, the Python install manager will use your system-wide proxy settings,

including automatic authentication. For most users, this behaves the same as

your browser and other applications.

To override the settings, use the ``NO_PROXY``, ``HTTP_PROXY`` and

``HTTPS_PROXY`` environment variables. These should be set in the terminal

session before using the Python install manager. Other applications may also

use the variables, so use caution before setting them globally for your entire

machine.

Setting ``NO_PROXY`` to any non-empty value will disable the use of any proxy.

Use this to bypass your system's default proxy setting and attempt to access the

index server directly.

Setting ``HTTPS_PROXY`` to a string like ``example.com:8080`` will connect to

that proxy server for all HTTPS connections. For the default index, all

connections will be using HTTPS, and so this is the usual setting to override.

The ``HTTP_PROXY`` variable may be needed if you are using a private index

server that does not use encrypted connections, but does require the default

proxy server to be overridden. It follows the same format as ``HTTPS_PROXY``.

Credentials may be embedded in either setting, however, when ``HTTPS_PROXY`` has

credentials embedded they will be used in preference to other credentials. Only

one set of credentials will be used for both types of proxy.

.. _pymanager-troubleshoot:

Troubleshooting

---------------

If your Python install manager does not seem to be working correctly,

work through these tests and fixes to see if it helps. If not, report an

issue at `our bug tracker <https://github.com/python/pymanager/issues>`_,