oracle/graalpython

GraalPy, the GraalVM Implementation of Python

GraalPy is a high-performance implementation of the Python language for the JVM built on GraalVM. GraalPy is a Python 3.12 compliant runtime. It has first-class support for embedding in Java and can turn Python applications into fast, standalone binaries. GraalPy is ready for production running pure Python code and has experimental support for many popular native extension modules.

Contributing

This project welcomes contributions from the community. Before submitting a pull request, please review our contribution guide.

If you’re considering contributing to this repository, you need to sign the Oracle Contributor Agreement before we can merge your changes. Also, review the Code of Conduct for contributors.

Why GraalPy?

Low-overhead integration with Java and other languages

• Use Python in Java applications on GraalVM JDK, Oracle JDK, or OpenJDK
• Use JVM tools like Maven, JFR, or GraalVM Native Image
• Manage Python libraries' system access thanks to GraalPy's Java-based emulation of Python OS APIs

Compatible with the Python ecosystem

• Use almost any standard Python feature, the CPython tests run on every commit and pass ~85%
• See if the packages you need work according to our Python Compatibility Checker
• Support for native extension modules is considered experimental, but you can already install packages like NumPy, PyTorch, or Tensorflow; run Hugging Face models like Stable Diffusion or GPT ^{We run the tests of the most depended on PyPI packages every day. For 93% of those 600 packages a recent version can be installed on GraalPy and GraalPy passes over 65% of all tests of all packages combined. We assume that CPython not passing 100% of all tests is due to problems in our infrastructure that may also affect GraalPy. Packages where CPython fails all tests are marked as "not tested" for both CPython and GraalPy.}

Runs Python code faster

• Pure Python code is often faster than on CPython after JIT compilation
• C extension performance is near CPython, but varies depending on the specific interactions of native and Python code
• GraalPy is geomean ~4x faster than CPython on the official Python Performance Benchmark Suite ^{Benchmarks run via pip install pyperformance && pyperformance run on each of CPython and GraalPy. Each interpreter was installed via pyenv.}

Getting Started

    - name: Setup GraalPy
      uses: actions/setup-python@v5
      with:
        python-version: graalpy # or graalpy24.2 to pin a version

Examples

^{Java AWT app with Python graph library using JBang  |  Standalone binary of a Python game by Joey Navarro with all dependencies included.}

Documentation

GraalPy Quick Reference Sheet should help you get started. More GraalPy-specific user documentation is available in docs/user. General documentation about polyglot programming and language embedding is available on the GraalVM website.

Community

The best way to get in touch with us is to join the #graalpy channel on GraalVM Slack or tweet us.

Security

Consult the security guide for our responsible security vulnerability disclosure process.

License

This GraalVM implementation of Python is Copyright (c) 2017, 2026 Oracle and/or its affiliates and is made available to you under the terms the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl/. This implementation is in part derived from and contains additional code from 3rd parties, the copyrights and licensing of which is detailed in the LICENSE and THIRD_PARTY_LICENSE files.