Getting Started

Python Requirements

PyOxidizer currently targets Python 3.8 or 3.9. Your Python application will need to already be compatible with 1 of these versions for it to work with PyOxidizer. See Why is Python 3.8 Required? for more on the minimum Python requirement.


Installing Rust

PyOxidizer is a Rust application and requires Rust (1.40 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 1.46.0 (04488afe3 2020-08-24)

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.


A cargo build from the repository root directory will likely fail due to how some of the Rust crates are configured.

See Using Cargo with PyOxidizer Source Checkouts for instructions on how to invoke cargo.

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

$ pyoxidizer
PyOxidizer 0.8-pre
Gregory Szorc <>
Build and distribute Python applications

    pyoxidizer [FLAGS] [SUBCOMMAND]


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

High-Level Project Lifecycle

PyOxidizer exposes various functionality through the interaction of pyoxidizer commands and configuration files.

The first step of any project is to create it. This is achieved with a pyoxidizer init-* command to create files required by PyOxidizer.

After that, various pyoxidizer commands can be used to evaluate configuration files and perform actions from the evaluated file. PyOxidizer provides functionality for building binaries, installing files into a directory tree, and running the results of build actions.

Your First PyOxidizer Project

The pyoxidizer init-config-file command will create a new PyOxidizer configuration file in a directory of your choosing:

$ pyoxidizer init-config-file 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 configuration created by pyoxidizer init-config-file will produce an executable that embeds Python and starts a Python REPL by default. Let’s test that:

$ cd pyapp
$ pyoxidizer run
resolving 1 targets
resolving target exe
    Compiling pyapp v0.1.0 (/tmp/pyoxidizer.nv7QvpNPRgL5/pyapp)
     Finished dev [unoptimized + debuginfo] target(s) in 26.07s
writing executable to /home/gps/src/pyapp/build/x86_64-unknown-linux-gnu/debug/exe/pyapp

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 The pyoxidizer Command Line Tool to learn more about the pyoxidizer tool. Or read on for a preview of how to customize your application’s behavior.

The pyoxidizer.bzl Configuration File

The most important file for a PyOxidizer project is the pyoxidizer.bzl configuration file. This is a Starlark file evaluated in a context that provides special functionality for PyOxidizer.

Starlark is a Python-like interpreted language and its syntax and semantics should be familiar to any Python programmer.

From a high-level, PyOxidizer’s configuration files define named targets, which are callable functions associated with a name - the target - that resolve to an entity. For example, a configuration file may define a build_exe() function which returns an object representing a standalone executable file embedding Python. The pyoxidizer build command can be used to evaluate just that target/function.

Target functions can call out to other target functions. For example, there may be an install target that creates a set of files composing a full application. Its function may evaluate the exe target to produce an executable file.

See Configuration Files for comprehensive documentation of pyoxidizer.bzl files and their semantics.

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.

The autogenerated pyoxidizer.bzl file created as part of running pyoxidizer init-config-file defines how your application is configured and built. It controls everything from what Python distribution to use, which Python packages to install, how the embedded Python interpreter is configured, and what code to run in that interpreter.

Open pyoxidizer.bzl in your favorite editor and find the line passing a run_repl argument, which configures the embedded interpreter to run a Python REPL. Let’s replace that line with the following:

run_eval="import uuid; print(uuid.uuid4())",

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

$ pyoxidizer run
   Compiling pyapp v0.1.0 (/home/gps/src/pyapp)
    Finished dev [unoptimized + debuginfo] target(s) in 3.92s
     Running `target/debug/pyapp`
writing executable to /home/gps/src/pyapp/build/x86_64-unknown-linux-gnu/debug/exe/pyapp

It works!

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

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

Find the exe = dist.to_python_executable( line in the pyoxidizer.bzl file. Let’s add a new line to make_exe() just below where exe is assigned:

for resource in exe.pip_install(["pyflakes==2.2.0"]):
    resource.add_location = "in-memory"

In addition, replace the run_* argument to execute pyflakes:

run_eval="from pyflakes.api import main; main()",

Now let’s try building and running the new configuration:

$ pyoxidizer run -- --help
   Compiling pyapp v0.1.0 (/home/gps/src/pyapp)
    Finished dev [unoptimized + debuginfo] target(s) in 5.49s
writing executable to /home/gps/src/pyapp/build/x86_64-unknown-linux-gnu/debug/exe/pyapp
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 The pyoxidizer Command Line Tool to learn more about the pyoxidizer tool.