Pytonium

Build Python desktop apps with HTML, CSS, and JavaScript.

Pytonium embeds the Chromium Embedded Framework (CEF 145 / Chromium 145) in Python, giving you the full power of modern web technologies for your desktop application UI.

Install

pip install Pytonium

Quick Start

import time
from Pytonium import Pytonium

p = Pytonium()
p.initialize("https://example.com", 800, 600)

while p.is_running():
    time.sleep(0.01)
    p.update_message_loop()

That's it -- a native desktop window running a full Chromium browser, in 7 lines of Python.

Features

• Chromium rendering -- Full browser engine for HTML/CSS/JS, use React, Tailwind, or any web framework
• Python-JS bridge -- Call Python functions from JavaScript, return values via Promises
• State management -- Shared state between Python and JS with namespace subscriptions and DOM events
• Custom URL schemes -- Map myapp:// to a local folder for loading HTML, assets, and 3D models
• Frameless windows -- Build custom window chrome with HTML/CSS, Electron-style
• Window control -- Position, size, minimize, maximize, fullscreen, drag, native handle access
• Multi-instance -- Run multiple browser windows in a single process
• TypeScript definitions -- Auto-generate .d.ts files for IDE auto-completion
• Async support -- asyncio integration with run_pytonium_async
• Event callbacks -- React to title changes, URL navigation, and fullscreen state
• Cross-platform -- Windows 11 and Linux

Example: Python + JavaScript Interop

from Pytonium import Pytonium, returns_value_to_javascript

p = Pytonium()

@returns_value_to_javascript("any")
def get_data():
    return {"answer": 42, "source": "Python"}

p.bind_function_to_javascript(get_data, javascript_object="api")
p.initialize("file:///path/to/index.html", 800, 600)

while p.is_running():
    p.update_message_loop()

// In your HTML/JS -- wait for bindings, then call Python
if (window.PytoniumReady) {
    callPython();
} else {
    window.addEventListener('PytoniumReady', callPython);
}

async function callPython() {
    const result = await Pytonium.api.get_data();
    console.log(result.answer); // 42
}

Examples

Complete examples are included in the pytonium_examples/ directory:

Documentation

Full documentation is available at maximilian-winter.github.io/pytonium, covering:

• Getting Started -- Installation, quick start, and first app tutorial
• Guides -- JS bindings, state management, frameless windows, async, and more
• API Reference -- Complete Pytonium class reference (~35 methods)
• Examples -- Walkthroughs of each example app
• Building from Source -- Windows and Linux build instructions

Platform Support

Building from Source

See the Build Guide or how-to-build-from-source.md for detailed instructions.

# Quick version (Windows)
pip install build scikit-build cmake ninja Cython
cmake -B cmake-build-release -DCMAKE_BUILD_TYPE=Release
cmake --build cmake-build-release --target pytonium_subprocess --config Release
cd building_pythonium_core && python prepare_build.py --platform windows --build-dir ../cmake-build-release
cd ../src/pytonium_python_framework && python -m build --wheel
pip install dist/pytonium-*.whl --force-reinstall

License

MIT License -- Pytonium also includes CEF (BSD) and nlohmann/json (MIT).