Getting Started


Installing Rust

PyOxidizer is a Rust application and requires Rust (1.36 or newer) to be installed in order to build PyOxidizer itself as well as Python application binaries.

You can verify your installed version of Rust by running:

$ rustc --version
rustc 1.38.0 (625451e37 2019-09-23)

If you don’t have Rust installed, has very detailed instructions on how to install it.

Rust releases a new version every 6 weeks and language development moves faster than other programming languages. It is common for the Rust packages provided by common package managers to lag behind the latest Rust release by several releases. For that reason, use of the rustup tool for managing Rust is highly recommended.

If you are a security paranoid individual and don’t want to follow the official rustup install instructions involving a curl | sh (your paranoia is understood), you can find instructions for alternative installation methods at

Other System Dependencies

You will need a working C compiler/toolchain in order to build some Rust crates and their dependencies. If Rust cannot find a C compiler, it should print a message at build time and give you instructions on how to install one.

There is a known issue with PyOxidizer on Fedora 30+ that will require you to install the libxcrypt-compat package to avoid an error due to a missing file. See for more info.

Installing PyOxidizer

PyOxidizer can be installed from its latest published crate:

$ cargo install pyoxidizer

From a Git repository using cargo:

# The latest commit in source control.
$ cargo install --git --branch main pyoxidizer

$ A specific release
$ cargo install --git --tag <TAG> pyoxidizer

Or by cloning the Git repository and building the project locally:

$ git clone
$ cd PyOxidizer
$ cargo install --path pyoxidizer


PyOxidizer’s project policy is for the main branch to be stable. So it should always be relatively safe to use main instead of a released version.

Once the pyoxidizer executable is installed, try to run it:

$ pyoxidizer
PyOxidizer 0.1
Gregory Szorc <>
Build and distribute Python applications

    pyoxidizer [SUBCOMMAND]


Congratulations, PyOxidizer is installed! Now let’s move on to using it.

Your First PyOxidizer Project

The pyoxidizer init command will create a new [Rust] project which supports embedding Python. Invoke it with the directory you want to create your new project in:

$ pyoxidizer init pyapp

This should have printed out details on what happened and what to do next. If you actually ran this in a terminal, hopefully you don’t need to continue following the directions here as the printed instructions are sufficient! But if you aren’t, keep reading.

The default project created by pyoxidizer init will produce an executable that embeds Python and starts a Python REPL by default. Let’s test that:

$ cd pyapp
$ pyoxidizer run
no existing PyOxidizer artifacts found
processing config file /home/gps/src/pyapp/pyoxidizer.bzl
resolving Python distribution...
   Compiling pyapp v0.1.0 (/home/gps/src/pyapp)
    Finished dev [unoptimized + debuginfo] target(s) in 53.14s
     Running `target/debug/testapp`

If all goes according to plan, you just started a Rust executable which started a Python interpreter, which started an interactive Python debugger! Try typing in some Python code:

>>> print("hello, world")
hello, world

It works!

(To exit the REPL, press CTRL+d or CTRL+z.)

Continue reading Managing Projects with pyoxidizer to learn more about the pyoxidizer tool. Or read on for a preview of how to customize your application’s behavior.

Customizing Python and Packaging Behavior

Embedding Python in a Rust executable and starting a REPL is cool and all. But you probably want to do something more exciting.

Inside the project’s root directory is an autogenerated pyoxidizer.bzl file. This file configures how the embedded Python interpreter is built as well as defines default run-time behavior. See New Project Layout if you are interested in what all the files do.

Open pyoxidizer.bzl in your favorite editor and find the python_run_mode variable. This type configures what to do when the interpreter starts. By default, it should be python_run_mode_repl(). Let’s comment that out or delete it and replace it with the following:

``python_run_mode = python_run_mode_eval("import uuid; print(uuid.uuid4())")``

We’re now telling the interpreter to effectively run the Python statement eval(import uuid; print(uuid.uuid4()) when it starts. Test that out:

$ pyoxidizer run
   Compiling pyembed v0.1.0 (/home/gps/src/pyapp/pyembed)
   Compiling pyapp v0.1.0 (/home/gps/src/pyapp)
    Finished dev [unoptimized + debuginfo] target(s) in 3.92s
     Running `target/debug/pyapp`

It works!

This is still pretty trivial. But it demonstrates how the pyoxidizer.bzl is used to influence the behavior of built binaries.

Let’s do something a little bit more complicated, like package an existing Python application!

Find where the packaging rules are passed to the Config(...) function (typically at the bottom of the file). Let’s add an additional packaging rule:

package_pyflakes = PipInstallSimple(package="pyflakes==2.1.1")
python_run_mode = python_run_mode_eval("from pyflakes.api import main; main()")

   packaging_rules=[stdlib, stdlib_extensions_policy, package_pyflakes],

This tells PyOxidizer that you want to install version 2.1.1 of the pyflakes package. At build time, this will effectively perform a pip install pyflakes==2.1.1 and take all installed files and add them to the produced binary. Let’s try that:

$ pyoxidizer run -- --help
   Compiling pyembed v0.1.0 (/home/gps/tmp/pyapp/pyembed)
   Compiling pyapp v0.1.0 (/home/gps/tmp/pyapp)
    Finished dev [unoptimized + debuginfo] target(s) in 5.49s
     Running `target/debug/pyapp --help`
Usage: pyapp [options]

  --version   show program's version number and exit
  -h, --help  show this help message and exit

You’ve just produced an executable for pyflakes!

There are far more powerful packaging and configuration settings available. Read all about them at Configuration Files and Packaging User Guide. Or continue on to Managing Projects with pyoxidizer to learn more about the pyoxidizer tool.