Pywebview 6 2 0

pywebview 6.2

Overview

pywebview is a lightweight BSD-licensed cross-platform wrapper around native webview components. It displays HTML content in its own native GUI window, giving you the power of web technologies in a desktop application while hiding the fact that the UI is browser-based.

Key capabilities:

• Cross-platform — Windows (WinForms/EdgeChromium/CEF), macOS (Cocoa/WebKit), Linux (GTK or Qt), Android (Kivy)
• Two-way JavaScript↔Python communication — call Python from JS and JS from Python without HTTP
• Built-in HTTP server — serves local files automatically via Bottle
• DOM support in Python — manipulate and traverse DOM nodes without JavaScript
• Window management — size, position, fullscreen, frameless, multi-window
• Native components — menus, file dialogs, confirmation dialogs
• Bundler-friendly — works with PyInstaller, Nuitka, py2app
• Shared state (new in 6.0) — reactive state object synced between Python and JavaScript

pywebview does not bundle a heavy GUI toolkit or web renderer, keeping frozen executables small.

Requires Python 3.8+.

When to Use

• Building desktop applications with HTML/CSS/JavaScript UIs
• Wrapping existing web applications in a native window
• Creating tools that need two-way communication between Python backend and JavaScript frontend
• Prototyping GUIs quickly with web technologies
• Building cross-platform desktop apps without learning platform-specific GUI frameworks
• Distributing Python apps with embedded web content via PyInstaller, Nuitka, or py2app

Installation

pip install pywebview

On Linux, choose a backend explicitly:

pip install pywebview[gtk]   # GTK + WebKit2
pip install pywebview[qt]    # PyQt6 + QtWebEngine
pip install pywebview[qt5]   # PyQt5
pip install pywebview[pyside6]  # PySide6

Optional extras:

• pywebview[cef] — CEF renderer (Windows only)
• pywebview[ssl] — SSL support for local HTTP server
• pywebview[android] — Android support

Hello World

import webview

webview.create_window('Hello world', 'https://pywebview.flowrl.com/')
webview.start()

Core Concepts

Application Lifecycle

1. Create windows with webview.create_window() before or during the GUI loop
2. Start the GUI loop with webview.start() — this blocks until all windows are closed
3. Backend logic runs in a separate thread via webview.start(func, *args)

import webview

def backend_logic(window):
    """Runs in a separate thread after the GUI loop starts."""
    window.toggle_fullscreen()

window = webview.create_window('My App', html='<h1>Hello</h1>')
webview.start(backend_logic, window)
# Code below runs only after all windows are closed

Content Loading

Three ways to load content into a window:

• URL — remote or local path (relative paths auto-start HTTP server)
• HTML string — inline HTML content
• WSGI app — pass a Flask/FastAPI app object directly

# Remote URL
webview.create_window('Docs', 'https://pywebview.flowrl.com/')

# Inline HTML
webview.create_window('Inline', html='<h1>Hello</h1>')

# Local files (HTTP server starts automatically for relative paths)
webview.create_window('Local', 'src/index.html')

# WSGI app
from flask import Flask
app = Flask(__name__, static_folder='./assets')
webview.create_window('Flask', app)

Multiple Windows

Create as many windows as needed. All windows are tracked in webview.windows:

import webview

first = webview.create_window('First', 'https://example.com')
second = webview.create_window('Second', 'https://other.com')

# Access the currently focused window
active = webview.active_window()
print(f'Active: {active.title}')
print(f'Total windows: {len(webview.windows)}')

webview.start()

Settings

Global settings override default behavior via webview.settings:

import webview

webview.settings['ALLOW_DOWNLOADS'] = True
webview.settings['OPEN_EXTERNAL_LINKS_IN_BROWSER'] = False
webview.settings['IGNORE_SSL_ERRORS'] = True

Available settings:

• ALLOW_DOWNLOADS — allow file downloads (default: False)
• ALLOW_FILE_URLS — enable file:// URLs (default: False)
• DRAG_REGION_SELECTOR — CSS selector for drag region in frameless windows
• DRAG_REGION_DIRECT_TARGET_ONLY — only direct matches are draggable
• OPEN_EXTERNAL_LINKS_IN_BROWSER — open target=_blank links externally (default: True)
• OPEN_DEVTOOLS_IN_DEBUG — auto-open DevTools in debug mode (default: True)
• IGNORE_SSL_ERRORS — ignore SSL certificate errors (default: False)
• REMOTE_DEBUGGING_PORT — port for remote debugging (edgechromium/qt)
• SHOW_DEFAULT_MENUS — show default menus on macOS (default: True)
• WEBVIEW2_RUNTIME_PATH — path to bundled WebView2 runtime

Usage Examples

Basic Window with Events

import webview

def on_closing():
    print('Window is about to close')

def on_loaded(window):
    print(f'Page loaded: {window.get_current_url()}')

window = webview.create_window('My App', 'https://example.com')
window.events.closing += on_closing
window.events.loaded += lambda: on_loaded(window)
webview.start()

JavaScript to Python Communication

import webview

class Api:
    def greet(self, name):
        return f'Hello, {name}!'

    def add(self, a, b):
        return a + b

html = '''
<button Python</button>
<script>
  window.addEventListener('pywebviewready', () => {
    pywebview.api.greet('World').then(result => alert(result));
  });
</script>
'''

webview.create_window('JS API', html=html, js_api=Api())
webview.start()

Shared State (6.0+)

import webview

html = '''
<button
<span id="counter"></span>
<script>
  window.addEventListener('pywebviewready', () => {
    pywebview.state.addEventListener('change', e => {
      document.getElementById('counter').innerText = pywebview.state.counter;
    });
  });
</script>
'''

def on_change(event_type, key, value):
    print(f'{event_type}: {key} = {value}')

window = webview.create_window('State', html=html)
window.state.counter = 0
window.state += on_change
webview.start()

Window with SSL and Custom User Agent

import webview

webview.create_window('Secure', 'src/index.html')
webview.start(ssl=True, user_agent='MyApp/1.0')

Advanced Topics

Full API Reference: create_window, start, Window methods, events → API Reference

JavaScript↔Python Bridge: JS API, expose, shared state, evaluate_js, run_js → JavaScript-Python Bridge

DOM Support: Element manipulation, traversal, events from Python → DOM Support

Platforms and Renderers: Web engines per platform, installation, dependencies → Platforms and Renderers

Advanced Topics: Freezing/bundling, security, debugging, HTTP server, menus, file dialogs → Advanced Topics