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v0.6.0 replaces the old pythonnet + .NET CLR + WebView2 WinForms backend with wryview, a Rust-powered binding for wry (the WebView engine used by Tauri).
This brings cross-platform support (Windows, macOS), faster startup (no .NET CLR), and access to the wry API (cookies, devtools, custom protocols, etc.). Linux is not yet supported (PRs welcome!).
See Migration Guide below if upgrading from v0.5.x.
QtWebView embeds a wry WebView as a native child window inside any Qt (PySide/PyQt) widget. Built on QtPy and wryview.
- Cross-Platform — Windows (WebView2), macOS (WKWebView). Same API everywhere. Linux not yet supported.
- Qt-Native Embedding — True QWidget via native child window, not a pseudo-overlay.
- JS Bridge — Two-way Python ↔ JavaScript communication with async/await support.
- WSGI Compatible — Run Flask, Bottle, Django inside the webview via custom protocol (no TCP server).
- Persistent Cache — Automatic user data folder for fast warm starts. Incognito mode available.
- Wry API — Cookies, devtools, zoom, print, drag-drop, custom headers, and more.
- Lazy Loading — Window appears instantly, WebView loads in background.
pip install qtwebview2
# You also need a Qt backend:
pip install pyside6 # or pyqt6import sys
from qtpy.QtWidgets import QApplication, QVBoxLayout, QWidget
from qtwebview2 import QtWebViewWidget
app = QApplication(sys.argv)
win = QWidget()
win.setWindowTitle("QtWebView")
win.resize(800, 600)
layout = QVBoxLayout(win)
webview = QtWebViewWidget(url="https://example.com", parent=win)
layout.addWidget(webview)
win.show()
sys.exit(app.exec())### JS Bridge — Python ↔ JavaScript
Expose Python functions to JavaScript with DictJsBridge. JS calls Python via
window.qtwebview.api.funcName() — with full Promise / async / await support.
import sys
from qtpy.QtWidgets import QApplication, QVBoxLayout, QWidget
from qtpy.QtCore import Slot, QCoreApplication
from qtwebview2 import QtWebViewWidget, DictJsBridge
# Set an application name so the user data folder path stays stable
QCoreApplication.setApplicationName("QtWebView-Demo")
# 1. Initialize app and window
app = QApplication(sys.argv)
win = QWidget()
win.setWindowTitle("JS Bridge Demo")
win.resize(800, 600)
layout = QVBoxLayout(win)
# 2. Create JS bridge instance
js_bridge = DictJsBridge()
# 3. Create WebView widget with JS bridge injected
webview = QtWebViewWidget(js_apis=js_bridge, debug=True)
layout.addWidget(webview)
# 4. (JS -> Python) Define a Python function and expose it to JavaScript
@js_bridge.bind_js_api_func
def get_user_os():
"""This Python function will be callable from JavaScript."""
print(f"Python function 'get_user_os' was called from JavaScript!")
return sys.platform
# 5. Define HTML content with JavaScript that calls Python
html_content = """
<!DOCTYPE html>
<html>
<head><title>JS Bridge Test</title></head>
<body style="font-family: sans-serif; text-align: center; background-color: #f0f0f0;">
<h1>QtWebView JS Bridge Demo</h1>
<button onclick="callPython()">Click to Call Python!</button>
<p>Result from Python: <b id="result">...</b></p>
<script>
async function callPython() {
try {
// Call Python function with async/await and get the result
const os = await window.qtwebview.api.get_user_os();
document.getElementById('result').textContent = os;
} catch (e) {
document.getElementById('result').textContent = 'Error: ' + e;
}
}
</script>
</body>
</html>
"""
webview.load_html(html_content)
# 6. Python -> JS: Execute JavaScript after page loads
@Slot(str, str)
def on_page_loaded(evt, url):
if evt == "Finished":
webview.evaluate_js("""(function() {
const new_element = document.createElement('h2');
new_element.textContent = 'Hello from Python!';
document.body.appendChild(new_element);
})()""")
webview.signals.page_loaded.connect(on_page_loaded)
win.show()
sys.exit(app.exec())### WSGI — Flask / Bottle / Django
Run your WSGI app inside the webview. Requests are served via custom protocol
(qtwebview:// scheme) — no TCP port, zero network overhead. Or switch to
localhost mode with wsgi_scheme="localhost".
import sys
import random
from datetime import datetime
from flask import Flask, jsonify, render_template_string
from qtpy.QtWidgets import (QApplication, QVBoxLayout, QHBoxLayout,
QWidget, QLabel, QPushButton, QFrame)
from qtpy.QtCore import Qt
from qtwebview2 import QtWebViewWidget
# ── Flask app ───────────────────────────────────────────────────────
flask_app = Flask(__name__)
HTML_TEMPLATE = """
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<style>
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
Helvetica, Arial, sans-serif;
background: #f5f7fa; color: #2c3e50;
display: flex; justify-content: center; align-items: center;
min-height: 100vh;
}
.card {
background: #fff; width: 90%; max-width: 520px;
padding: 40px; border-radius: 12px;
box-shadow: 0 4px 20px rgba(0,0,0,0.08); text-align: center;
}
h1 { color: #34495e; margin-bottom: 8px; }
.tag {
display: inline-block; background: #e1f5fe; color: #0288d1;
padding: 3px 8px; border-radius: 4px; font-size: 0.85em;
font-weight: 600; margin-bottom: 20px;
}
button {
padding: 10px 24px; background: #00c853; color: #fff;
border: none; border-radius: 6px; cursor: pointer; font-size: 15px;
transition: background 0.2s; margin-top: 16px;
}
button:hover { background: #00e676; }
#result-box {
margin-top: 20px; padding: 16px; background: #263238;
color: #80cbc4; border-radius: 6px; font-family: "Fira Code",
"Cascadia Code", Consolas, monospace; text-align: left;
min-height: 60px; white-space: pre-wrap; font-size: 13px;
}
</style>
</head>
<body>
<div class="card">
<h1>🐍 Flask + 🖥️ QtWebView</h1>
<span class="tag">WSGI · Custom Protocol</span>
<p>Server Time: <strong>{{ time }}</strong></p>
<button onclick="fetchData()">⚡ Fetch JSON from Flask</button>
<div id="result-box">// Click the button...</div>
</div>
<script>
async function fetchData() {
const box = document.getElementById('result-box');
box.textContent = '// Loading...';
try {
const res = await fetch('/api/random', { method: 'POST' });
const data = await res.json();
box.textContent = JSON.stringify(data, null, 2);
} catch (e) {
box.textContent = 'Error: ' + e;
}
}
</script>
</body>
</html>
"""
@flask_app.route("/")
def index():
return render_template_string(HTML_TEMPLATE,
time=datetime.now().strftime("%H:%M:%S"))
@flask_app.route("/api/random", methods=["POST"])
def api_random():
return jsonify({
"value": random.randint(1000, 9999),
"source": "Flask Backend",
"status": "success",
})
# ── Qt Window ───────────────────────────────────────────────────────
class MainWindow(QWidget):
def __init__(self):
super().__init__()
self.setWindowTitle("QtWebView WSGI Demo")
self.resize(900, 640)
layout = QVBoxLayout(self)
layout.setContentsMargins(0, 0, 0, 0)
layout.setSpacing(0)
# Toolbar
bar = QFrame()
bar.setFixedHeight(44)
bar.setStyleSheet("""
QFrame { background: #fff; border-bottom: 1px solid #e0e0e0; }
QLabel { color: #333; font-size: 13px; font-weight: 600; }
QPushButton {
background: transparent; border: 1px solid #ccc;
border-radius: 4px; padding: 4px 14px; color: #555;
}
QPushButton:hover { background: #f0f0f0; color: #000; }
""")
bar_layout = QHBoxLayout(bar)
bar_layout.setContentsMargins(12, 0, 12, 0)
bar_layout.addWidget(QLabel("🚀 QtWebView WSGI Demo"))
bar_layout.addStretch()
reload_btn = QPushButton("Reload")
reload_btn.setCursor(Qt.CursorShape.PointingHandCursor)
reload_btn.clicked.connect(self._reload)
bar_layout.addWidget(reload_btn)
layout.addWidget(bar)
# WebView — WSGI served via qtwebview:// scheme
self.webview = QtWebViewWidget(
parent=self, wsgi_app=flask_app, debug=True
)
layout.addWidget(self.webview, 1)
def _reload(self):
self.webview.reload()
if __name__ == "__main__":
app = QApplication(sys.argv)
win = MainWindow()
win.show()
sys.exit(app.exec())By default, QtWebViewWidget uses an independent anchor window
(native_child=False) — the WebView survives parent hide/show cycles on
Windows. Tray apps work out of the box.
If you opt into the old direct-child mode with native_child=True, the
WebView is a native child of the Qt widget and will be destroyed when the
parent HWND is torn down:
# Only needed for native_child=True:
def closeEvent(self, event):
event.ignore() # don't destroy the native window
self.hide() # just hide — WebView stays alive| QtWebView (v0.6.0+) | pywebview | QWebEngineView | |
|---|---|---|---|
| Qt Integration | ✅ Native QWidget | ✅ Native | |
| Cross-Platform | ✅ Win/Mac | ✅ | ✅ |
| Package Size | ✅ Small (wryview <1MB) | Small | ❌ Large (>160MB) |
| WSGI | ✅ Custom protocol (portless) | Local HTTP | QWebChannel |
| JS Bridge | ✅ Promise/async | ✅ | |
| Startup | ~1-2s | ~1-3s | ~2-3s |
| Semi-transparent | ❌ System limit | ❌ System limit | ✅ Native blend |
Airspace Issue: On Windows, HWND child windows and Qt native rendering use separate rendering pipelines. Opaque Qt widgets placed on top of the WebView display correctly, but semi-transparent widgets only blend with the Qt window underneath — they will not blend with WebView content. This is a Win32 windowing system limitation; QWebEngineView avoids it by using Qt's native rendering pipeline.
# Old (v0.5.x) → New (v0.6.0)
from qtwebview2 import QtWebView2Widget from qtwebview2 import QtWebViewWidget
webview = QtWebView2Widget(url=...) webview = QtWebViewWidget(url=...)
# Parameters with different names:
# handle_new_window=True/False → new_window_handler=lambda url: "allow"|"deny"
# wsgi_host_name="myapp.local" → wsgi_scheme="qtwebview"
# browser_executable_folder=... → (not supported by wry)
# fullscreen_support=True → fullscreen_handler=your_handler
# no_local_storage=True → (removed, use incognito=True)
# Removed parameters (no equivalent):
# context_menus, init_settings_hook
# New parameters in v0.6.0:
# html, headers, navigation_handler, incognito, autoplay,
# javascript_enabled, hotkeys_zoom, drag_drop_handler,
# js_apis, wsgi_executor, fullscreen_handler, parent, native_childwebview = QtWebViewWidget(
url="https://example.com", # initial URL
html="<h1>Hello</h1>", # or initial HTML
headers={"Authorization": "Bearer"}, # custom HTTP headers
user_agent="CustomAgent/1.0",
debug=True, # DevTools on
transparent=False,
background_color="#1e1e1e",
navigation_handler=lambda url: True, # return False to block
new_window_handler=lambda url: "allow",
lazyload=True, # defer to showEvent
js_apis=DictJsBridge(), # JS API bridge
incognito=False,
user_data_folder="/path/to/cache",
wsgi_app=flask_app,
wsgi_scheme="qtwebview",
wsgi_executor=8, # WSGI thread pool size
autoplay=False,
javascript_enabled=True,
hotkeys_zoom=True,
drag_drop_handler=lambda evt, paths, pos: True,
fullscreen_handler=lambda enter: ..., # custom fullscreen behavior
native_child=False, # anchor window mode
parent=self, # parent QWidget
)
webview.load_url(url) # Navigate
webview.load_url_with_headers(url, hdrs) # Navigate with headers
webview.load_html(html) # Load HTML
webview.reload() # Reload
webview.url() # Get current URL
webview.eval_js(script) # Execute JS
webview.evaluate_js(script, callback) # Execute JS with callback
webview.cookies() # Get all cookies
webview.cookies_for_url(url) # Get cookies for a URL
webview.set_cookie(name, value) # Set cookie
webview.delete_cookie(name, url) # Delete cookie
webview.open_devtools() # Open DevTools
webview.close_devtools() # Close DevTools
webview.zoom(1.5) # Zoom 150%
webview.print() # Print page
webview.focus() # Focus webview
webview.set_background_color(r, g, b, a) # Set background color
webview.clear_all_browsing_data() # Clear cache
# Signals
webview.signals.page_loaded.connect(lambda evt, url: ...)
webview.signals.title_changed.connect(lambda title: ...)
webview.signals.navigation_requested.connect(lambda url: ...)
webview.signals.new_window_requested.connect(lambda url: ...)
webview.signals.web_message_received.connect(lambda msg: ...)
webview.signals.initialization_done.connect(lambda: ...)Copyright (c) 2025-2026 Xiaosu.
Distributed under the terms of the Mozilla Public License Version 2.0.