tpac

WebView Quirks and Testing Breakout TPAC 2025

Nov. 11, 2025 08:30 GMT+9

Link: https://bit.ly/webview-cg-2510

Notes on GitHub:https://github.com/WebView-CG/tpac/blob/main/TPAC-2025/Breakout/WebViewQuirksAndTestingNotes.md

Session goals

• Showcase testing tools
• In progress testing resources
• Open exchange about WebView issues

Attendees

• Niklas Merz (Apache Cordova)
• Bryan Ellis (Apache Cordova)
• Dan Pelegero (RPGC Group)
• Karl Dubost (Apple - WebKit Webcompat)
• SANG UI PARK
• Euclid (Huawei)
• Mingyu Lei (Google Chrome)
• Ben Kelly (Meta)

Scribes

• Bryan Ellis

Agenda

• Introduction round
• Present CanIWebview apps and ideas (Niklas)
• Test automations are being built
• Let’s share our stories, issues and use cases with WebView
• Cookies and localhost (Niklas)
• ….more

Notes

• Niklas:
  • Going over the CanIWebView.com website that was built to collect and display data.
    • Cover major browsers. Data collected from BCD
  • Built basic apps to allow developers to test webviews.
    • Testing WebViews should be accessible for every web developer
    • The apps are built and published for Android and iOS
    • Can download and build locally for WebView 2 (Windows)
    • Working on an experimental build for Taui + Servo
    • The apps are open source and ad-free + offer all WebView configurations
  • Next big step is to create automation for testing (App driver & Web driver)
  • Shows screenshots & demoing the CanIWebview App
    • Showing that from within the app can run the mdn bcd collector to test what the webview is capable of.
    • Shows that the app can configure the webview settings. For example, enable or disable JavaScript.
    • Looking to have discussion around what type of additional configurations should be added.
  • Looking for anyone that has recent knowledge around App driver & Web driver
  • Niklas: Personal number one issue is how local contents are served differently between Android and iOS.
    • File protocol is not used as much anymore because of how major frameworks handle routing.
    • Android supports hosting content though HTTP/HTTPS registered domains. Can intercept GET & path
    • iOS must use a customer app URL scheme.
    • iOS has more flexibility and capability
    • Different origins need different HTTP allow origin headers and therefore the backend needs to support dynamically setting that
  • WebViews implement their own Cookies managers but there are quirks in how it works in WebViews.
• Karl: Would like to know what is missing from in terms of documentation of what webviews are.
• Niklas: One example is what information vendors release, for example when a new feature is released from WebKit is it in Safari only or also in WebView.
• Niklas: WebDX is trying to collect and create a baseline of what features exist and support in browsers and we are trying to create a similar baseline for WebViews.
  • Showing a demo of the CanIWebView’s baseline map…
• Karl: BCD data is not always up-to-date
• Karl: Apple is contributing back to BCD for data they find is wrong in their testing
• Niklas: Which platforms?
• Karl: Safari desktop & mobile
• Niklas: Would be good if Apple could also contribute back to BCD for WKWebView
• Ben:
  • Android, it seems easier to monitor events like onPageLoad which can be abused
  • Browsers for a long time store cookies on disk and would be loaded into memory but for some reason the document.cookie is slower.
  • A lot of things that can be done in Chrome are not mapped the same in the WebView, or is disabled.
• Euclid: Has experience with web drivers and will reach out to talk further about it.
• Dan: SPC Payments APIs - Browser handles the payment calls, what is the role that should exist.