Integrating Rust with Python: A Comprehensive Guide

Integrating Rust with Python: A Comprehensive Guide

Programming languages are not created equal. Some are more suited to certain tasks than others. Python and Rust are no exceptions. They both offer certain advantages when used in different domains. Python is highly expressive and perfect for writing short scripts. Rust, on the other hand, is known for its performance and safety. In this guide, we will explore how to combine these two languages to get the best of both worlds. We will cover how to integrate Rust with Python and look into specific examples to demonstrate their synergy. This guide is aimed at developers who have some experience in both Python and Rust and wish to integrate the two.

Why Integrate Rust With Python?

Rust is becoming increasingly popular for several reasons:

  • Performance: Rust is a compiled language, and it is designed for performance, offering similar or even better performance than C or C++.

  • Memory Safety: Rust's robust static type system, and its ownership model, prevent common programming errors like null pointer dereferencing, double free, etc.

  • Concurrency and Parallelism: Rust has first-class support for concurrent and parallel programming. Unlike Python, Rust doesn't have a Global Interpreter Lock (GIL) that can be a bottleneck for multithreaded programs.

Python, on the other hand, is loved for its simplicity and readability.

By integrating Rust with Python, you can keep the simplicity and expressiveness of Python while leveraging the performance and safety of Rust.

How to Integrate Rust with Python?

To integrate Rust with Python, you typically write some parts of the application that require better performance or safety in Rust. This Rust code is then compiled into a shared library which can be imported and used in a Python program.

Here's a step-by-step guide:

  1. Write the Rust Function: First, you write a function in Rust that you want to call in Python.
#[no_mangle] // ensures the function name is not mangled
pub extern "C" fn add(a: i32, b: i32) -> i32 {
    return a + b;
  1. Generate Shared Library: Compile your Rust function into a shared library.
$ rustc --crate-type cdylib -o
  1. Import and Use in Python: Use the ctypes library in Python to import and call your Rust function.
import ctypes

# Load the shared library
libadd = ctypes.CDLL('./')

# Use the function
result = libadd.add(2, 3)
print(result) # outputs 5

Which Module Makes It Easier to Integrate Rust and Python?

RustPython is a popular project that lets you run Python on Rust. However, for integrating Rust code into a Python project, PyO3 stands out. PyO3 is a Rust binding for Python interpreter that allows writing native Python modules or embedding Python interpreter in a Rust program.

use pyo3::prelude::*;

/// Formats the sum of two numbers as a string.
fn sum_as_string(a: usize, b: usize) -> PyResult<String> {
    Ok((a + b).to_string())

fn my_module(py: Python, m: &PyModule) -> PyResult<()> {
    m.add_function(wrap_pyfunction!(sum_as_string, m)?)?;

After implementing your functions, you use maturin or setuptools-rust to generate wheel files, which can be installed and used in Python just like any other package.

Can Rust Replace Python's Global Interpreter Lock (GIL)?

While Rust cannot replace Python's Global Interpreter Lock (GIL), it helps in handling the GIL more safely. It's an understood crust in Python programming that only one thread can execute Python bytecodes at a time, even in a multi-core environment. This restriction is known as the GIL. It allows for easier integration with C libraries and simplifies memory management.

Rust has a safer handling mechanism for variables. PyO3 provides some primitives like the GILGuard and the GILPool that help in handling the GIL and the Python heap respectively. They ensure that you, the programmer, don't inadvertently introduce runtime errors or memory leaks.


There is no silver bullet in programming. Each language comes with its trade-offs. The key is to use the right tool for the right job. By integrating Rust with Python, we can leverage Python's simplicity and readability while taking advantage of Rust's performance and safety. This allows us to create more efficient and safer applications.

As a developer, the idea of learning new languages and integrating them may seem challenging, but it is certainly beneficial. Dive into Rust if you haven't and start exploring how you can rewrite your critical Python code in Rust for better performance and safety. With new libraries like PyO3, this integration has become simpler and safer than ever before.

Disclaimer: The code snippets provided in this guide are for illustrative purposes only. Although they have been written with care, we recommend doing your own testing when integrating code from different programming languages.