I'm developing a cross-platform application using Tauri, which uses WebView technology as the GUI renderer. On macOS, it should be using WKWebView. Based on my tests, all applications developed with Tauri can only run at 60fps on macOS and cannot take advantage of ProMotion displays to achieve a 120fps refresh rate, whereas the same application can run at 120fps on other platforms. I have submitted this issue to Tauri on GitHub, and it appears that this cannot be resolved through external settings, but only by modifying the WKWebView code to support higher frame rates. Is there any possible solution to this?
Explore the integration of web technologies within your app. Discuss building web-based apps, leveraging Safari functionalities, and integrating with web services.
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Hi all,
I’m seeing a puzzling discrepancy in behavior between NSURLSession (with multipathServiceType = NSURLSessionMultipathServiceTypeInteractive) and WKWebView when the device is connected to a Wi-Fi SSID that has no internet (e.g., a hardware device’s AP). I have the Multipath entitlement properly enabled, and in this scenario:
NSURLSession requests automatically fall back to cellular and succeed (no user intervention, fast switch).
WKWebView loads fail or stall: the web content does not appear, and it seems like the web view is not using the cellular path even though the system network path becomes satisfied and real Internet reachability is confirmed.
Environment:
iOS version: (e.g., iOS 18.4)
Device: (e.g., iPhone 15 Pro)
Multipath entitlement: enabled in the app, using NSURLSessionMultipathServiceTypeInteractive
Connected SSID: hardware device Wi-Fi with no external internet
Expected fallback: automatic to cellular once the Wi-Fi has no internet, as observed with NSURLSession
What I’ve done / observed:
NSURLSession using Multipath works as expected:
NSURLSessionConfiguration *cfg = [NSURLSessionConfiguration defaultSessionConfiguration];
cfg.multipathServiceType = NSURLSessionMultipathServiceTypeInteractive;
NSURLSession *session = [NSURLSession sessionWithConfiguration:cfg];
NSURLRequest *req = [NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.apple.com/library/test/success.html"]];
NSURLSessionDataTask *task = [session dataTaskWithRequest:req completionHandler:^(NSData *data, NSURLResponse *resp, NSError *err) {
NSLog(@"NSURLSession result: %@, error: %@", resp, err);
}];
[task resume];
When connected to the device Wi-Fi (no external internet), the session quietly shifts to cellular and completes successfully.
WKWebView fails to load under the same conditions:
[self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.apple.com/library/test/success.html"]]];
The web view either shows a load failure or just hangs, even though lower-level monitoring reports that the network path is satisfied and real Internet connectivity is available.
Network path monitoring logic:
I use the C API nw_path_monitor to watch for nw_path_status_satisfied.
Once satisfied is observed, I perform a true connectivity check using nw_connection (e.g., connecting tohttps://www.apple.com/library/test/success.html) to verify that real Internet traffic can flow over cellular.
That check passes, confirming fallback to cellular, but WKWebView still does not load content. Meanwhile, NSURLSession requests in the same condition succeed immediately.
Sample logging trace:
[+] nw_path_status_satisfied=1, hasWiFi=1, hasCellular=1
[+] Internet connectivity test: ready (via nw_connection)
[-] WKWebView load failed / stalled
[+] NSURLSession request completed successfully
Questions:
Why does NSURLSession with the multipath service type seamlessly use cellular when the Wi-Fi has no internet, but WKWebView does not exhibit the same fallback behavior? Is WKWebView not honoring the system’s multipath fallback the same way? Does it use a different networking stack or ignore the multipath entitlement in this scenario?
Is there a supported way to force WKWebView to behave like NSURLSession here?
For example, can I bridge content through a multipath-enabled NSURLSession and inject it into WKWebView via a custom scheme?
Are there any WKWebView configuration flags, preferences, or policies that enable the same automatic interface switching?
Are there known limitations or documented differences in how WKWebView handles network interface switching, path satisfaction, or multipath compared to raw NSURLSession?
What I’ve ruled out / tried:
Verified the Multipath entitlement is included and active.
Confirmed network path is “satisfied” and that real Internet reachability succeeds before calling [webView loadRequest:].
Delayed the WKWebView load until after connectivity verification.
Observed that NSURLSession requests succeed under identical connectivity conditions.
Any insight into internal differences, recommended workarounds, or Apple-recommended patterns for making web content robust in a “Wi-Fi with no internet” + automatic fallback-to-cellular scenario would be greatly appreciated.
Thank you!
Is it possible to open the native app from a web extension?
I have tried creating a new tab that uses the app's URL scheme but the UI asking the user to open the app is not shown until the new page UI is dismissed.
Creating a tab with an HTTPS URL that the app is setup to handle does not work and always the link in a new tab.
I tried sending a message to the app extension and using NSExtensionContext.open(_:completionHandler:) but the URL is not opened and the closure received false, indicating it was not handled.
Having the option to link back to the native app would be very useful.
I recently updated my iPhone 12 to iOS 26. It seems there is a bug rendering Safari unable to "add to home screen" any website. Clicking the button displays a blank modal with Add button greyed out.
Topic:
Safari & Web
SubTopic:
General
Hello.
I have a project that loads a page using jquery 3.6.3 in WKWebView.
When I try this on iOS developer beta 4, WKWebView malfunctions and the page does not load properly.
If I remove jquery, the page loads.
Even if I update jquery to the latest version, the problem remains the same.
This problem did not occur until developer beta 3.
The log is as follows.
0x12107c170 - [PID=994] WebProcessProxy::didClose: (web process 0 crash)
0x12107c170 - [PID=994] WebProcessProxy::processDidTerminateOrFailedToLaunch: reason=Crash
Error acquiring assertion: <Error Domain=RBSAssertionErrorDomain Code=2 "Specified target process 994 does not exist" UserInfo={NSLocalizedFailureReason=Specified target process 994 does not exist}>
0x121138300 - ProcessAssertion::acquireSync Failed to acquire RBS assertion 'XPCConnectionTerminationWatchdog' for process with PID=994, error: (null)
0x132e00018 - [pageProxyID=9, webPageID=10, PID=994] WebPageProxy::processDidTerminate: (pid 994), reason=Crash
0x132e00018 - [pageProxyID=9, webPageID=10, PID=994] WebPageProxy::dispatchProcessDidTerminate: reason=Crash
Failed to terminate process: Error Domain=com.apple.extensionKit.errorDomain Code=18 "(null)" UserInfo={NSUnderlyingError=0x13357de30 {Error Domain=RBSRequestErrorDomain Code=3 "No such process found" UserInfo={NSLocalizedFailureReason=No such process found}}}
Failed to terminate process: Error Domain=com.apple.extensionKit.errorDomain Code=18 "(null)" UserInfo={NSUnderlyingError=0x13357f390 {Error Domain=RBSRequestErrorDomain Code=3 "No such process found" UserInfo={NSLocalizedFailureReason=No such process found}}}
Failed to terminate process: Error Domain=com.apple.extensionKit.errorDomain Code=18 "(null)" UserInfo={NSUnderlyingError=0x13357d770 {Error Domain=RBSRequestErrorDomain Code=3 "No such process found" UserInfo={NSLocalizedFailureReason=No such process found}}}
Hello,
I find it difficult to find information about this function, but Apple would allow you to download a Wallet ticket via a JWT signed token, without going through a pkpass, by calling the url https://wallet.apple.com/push/pass? Jwt= + jwt
I have made several attempts with a different payload, either I am redirected to the Apple Pay presentation page, or I have a 403 error. I think I'm on my way, but I must miss a step in my signature. Could someone help me and give me the structure or how to manage the key? At the moment I use an Identifiers type PassType ID linked to a Certificate.
Has anyone heard of this novelty? According to ChatGPT it should date from iOS 16-18 and potentially not be open to all devs.
Thank you!
Beautiful day
TLDR: I’m searching for a possibility to allow the usage of passkeys and hardware keys for any website in a wkwebview
INFO: The browser is macOS ONLY
Hi, I couldn’t really find documentation or forums posts on how to implement Webauthn for signin or hardware security keys for a second factor. Or rather where those events are triggered to be handled. In Safari you have that popover, that lets you either authenticate through Passwords or with a security key.
When I visit webauthn.io for testing and click either register or authenticate I get
Told not to present authorization sheet: Error Domain=com.apple.AuthenticationServicesCore.AuthorizationError Code=1 "(null)"
ASAuthorizationController credential request failed with error: Error Domain=com.apple.AuthenticationServices.AuthorizationError Code=1004 "(null)"
If I add
func webView(_ webView: WKWebView, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping @MainActor (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
and
func webView(_ webView: WKWebView, authenticationChallenge challenge: URLAuthenticationChallenge, shouldAllowDeprecatedTLS decisionHandler: @escaping @MainActor (Bool) -> Void)
it doesn’t seem to change anything.
I found something about the ASWebAuthenticationSessionWebBrowserSupported entitlement, but by my understanding this is used so a browser can get opened upon some other app calling a ASWebAuthenticationSession.
Has anyone some guidance for me? I feel like webauthn and yubikey support are important security measures for our users.
https://codeberg.org/miakoring/Amethyst/src/branch/main/Amethyst/Shared/ViewComponents/WebKit/WebViewModel.swift
is the code for my webviewmodel.
Delegates are in the Delecate folder https://codeberg.org/miakoring/Amethyst/src/branch/main/Amethyst/Shared/ViewComponents/WebKit
Is the new Observations API for WebPage not available in Beta 1 as demoed in the WWDC video? I get this error even though Observation is imported.
Hi,
How are we supposed to handle links with target="_blank" in the new SwiftUI WebView? I don't see anything in WebPage.NavigationDeciding or elsewhere that corresponds to the delegate method used for WKWebView.
I have a simple Safari extension which contains only Javascript and no native code.
Currently I have the placeholder SafariWebExtensionHandler.swift that Xcode created when I added the extension. It's not doing anything useful, but simply deleting it doesn't seem to work.
Can I have an extension that includes no native code?
I am currently operating an app using an embedded web server that communicates over local HTTP.
Recently, when opening Safari, I started encountering the following error message:
"Safari cannot open the page. Error: Failed to navigate to an HTTP URL with HTTPS-only mode enabled."
However, I am currently in a situation where switching to HTTPS is difficult. Are there any solutions to resolve this issue besides using HTTPS?
Thank you.🙏
Hi there,
I'm experiencing several crashes on JavaScriptCore pas_panic_on_out_of_memory_error, only on devices with tvOS 15.4 and 15.4.1. This happens with users using the app for several hours as well as 5 seconds after launching the app.
Devices: AppleTV6,2 and AppleTV5,3
Thread 14 —
JavaScriptCore pas_panic_on_out_of_memory_error (JavaScriptCore)
JavaScriptCore bmalloc_try_iso_allocate_impl_impl_slow (JavaScriptCore)
JavaScriptCore bmalloc_heap_config_specialized_local_allocator_try_allocate_small_segregated_slow (JavaScriptCore)
JavaScriptCore bmalloc_allocate_impl_casual_case (JavaScriptCore)
JavaScriptCore ***::String::String(char16_t const*, unsigned int) (JavaScriptCore)
JavaScriptCore JSC::LiteralParser<char16_t>::parsePrimitiveValue(JSC::VM&) (JavaScriptCore)
JavaScriptCore JSC::LiteralParser<char16_t>::parse(JSC::ParserState) (JavaScriptCore)
JavaScriptCore JSC::jsonProtoFuncParse(JSC::JSGlobalObject*, JSC::CallFrame*) (JavaScriptCore)
JavaScriptCore llint_entry (JavaScriptCore)
JavaScriptCore llint_entry (JavaScriptCore)
JavaScriptCore llint_entry (JavaScriptCore)
JavaScriptCore llint_entry (JavaScriptCore)
JavaScriptCore vmEntryToJavaScript (JavaScriptCore)
JavaScriptCore JSC::Interpreter::executeCall(JSC::JSGlobalObject*, JSC::JSObject*, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) (JavaScriptCore)
JavaScriptCore JSC::boundThisNoArgsFunctionCall(JSC::JSGlobalObject*, JSC::CallFrame*) (JavaScriptCore)
JavaScriptCore vmEntryToNative (JavaScriptCore)
JavaScriptCore JSC::Interpreter::executeCall(JSC::JSGlobalObject*, JSC::JSObject*, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) (JavaScriptCore)
JavaScriptCore JSC::profiledCall(JSC::JSGlobalObject*, JSC::ProfilingReason, JSC::JSValue, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) (JavaScriptCore)
JavaScriptCore JSObjectCallAsFunction (JavaScriptCore)
JavaScriptCore -[JSValue invokeMethod:withArguments:] (JavaScriptCore)
ITMLKit -[IKJSObject invokeMethod:withArguments:] (ITMLKit)
ITMLKit -[IKJSEventListenerObject invokeMethod:withArguments:thenDispatchEvent:extraInfo:] (ITMLKit)
ITMLKit __43-[IKJSXMLHTTPRequest setRequestReadyState:]_block_invoke (ITMLKit)
ITMLKit -[IKAppContext _doEvaluate:] (ITMLKit)
ITMLKit -[IKAppContext _evaluate:] (ITMLKit)
ITMLKit __41-[IKAppContext evaluate:completionBlock:]_block_invoke (ITMLKit)
ITMLKit -[IKAppContext _sourcePerform] (ITMLKit)
ITMLKit -[IKConcurrentEvaluator lockSchedulingForEvaluation:] (ITMLKit)
ITMLKit IKRunLoopSourcePerformCallBack (ITMLKit)
CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ (CoreFoundation)
CoreFoundation __CFRunLoopDoSource0 (CoreFoundation)
CoreFoundation __CFRunLoopDoSources0 (CoreFoundation)
CoreFoundation __CFRunLoopRun (CoreFoundation)
CoreFoundation CFRunLoopRunSpecific (CoreFoundation)
ITMLKit -[IKAppContext _jsThreadMain] (ITMLKit)
Foundation __NSThread__start__ (Foundation)
libsyste...ad.dylib _pthread_start (libsystem_pthread.dylib)
libsyste...ad.dylib thread_start (libsystem_pthread.dylib)
This issue seems very similar to this existing thread, although not sure its related
Hello!
While working with the new Apple Pay SDK for iOS 18, I encountered a bug. When using the Ukrainian language, in the modal displaying the QR code, I noticed that there is a missing bracket for the year variable. This causes incorrect data to be displayed in the QR code.
This seems to be a localization issue specifically with the Ukrainian language in the new SDK, as the bug does not occur with other languages like English.
Has anyone else experienced this? Any advice or information on this bug would be appreciated.
Thanks!
Hi all ,
I have 2 questions regaridng App Clips.
1 - can we directly invoke App Clips from a HTML Appclip experience url ?
We want to directly take users to the App Clips flow without showing App Clips cards or banner.
2 - Does Apple have a plan to support other modern mobile browsers such as Chrome , Edge and Firefox ?
Hi,
My app is using JavascriptCore to run the business logic in a javascript environment.
We are randomly seeing crashes when users move the app back to the foreground.
These crashes are reported by Firebase (I am attaching an example). I also tried to find them in Organizer, but the stacktraces don't match and I am not sure if they are pointing to the same error (I attach one just in case).
I was trying to investigate a little bit about this, but I could find any explanation about what pas_reallocation_did_fail would mean.
Here is our implementation:
-(void) enqueueCallback:(JSValue *)callback withArguments:(NSArray *)args exclusive:(BOOL)exclusive {
[self enqueueBlock:^{
@autoreleasepool {
[callback callWithArguments:args];
}
} exclusive:exclusive];
}
Basically, every JS block is enqueued and then run by a dedicated thread specific to our JSContext.
Can I get some help?
Thanks in advance!
Crashlytics.txt
2024-08-30_10-00-01.2572_-0400-f757f8306eda9679ec1b2ff90fbc66c4eb1fbee7.crash
Sometimes Safari is rendering the icon for an active extension in its original provided colored representation, other times Safari is applying an overlay color in line with the system's highlight color.
This difference can even be seen seen on the Safari Extensions Developer home page: https://developer.apple.com/safari/extensions/images/extensions-hero-large_2x.png
You will notice that Grammarly's icon is shown in it's original color format, while the others aren't.
Example of extensions where the icon is shown in color:
Bitwarden
Grammarly
1Password
Consent-O-Matic
I've compared the source code of Bitwarden and Consent-o-Matic with my own extension and cannot find any differences in the settings or image properties (resolution, DPI, file type, color profile). If I take the exact PNG source files from said open source extensions and replace them in my own source code, these icons show up in full color.
Does this perhaps mean there is a bug in Safari's processing of the icons where it fails to overlay the icon with the highlight color in some cases?
I and I assume many developers with me would like to understand what determines this difference. Ideally, there is a consistent UX where the end user has the choice between icons in color or highlight color overlay.
When you open the Directorate General of civil Aviation, India website then in the top bar bring the cursor to “Regulations and Guidance” under that there will be a drop down which will give numerous options. In that go to Centre Column “Civil Aviation Requirements”. Then click on ”Section 7” then click on “Part II”. Actually on a laptop it’s a 4 page document but on my iPad it’s just an image of the first page. I can’t read any of the PDF’s.
Topic:
Safari & Web
SubTopic:
General
Hello,
I am developing Safari Content Blocker extension and discovered that it frequently fails to load with large amount of rules. Currently I have over 45k and most of the time when I reload the extension on iOS 18 (iPhone 12) it ends with error:
Error Domain=NSCocoaErrorDomain Code=4097 "connection to service named com.apple.SafariServices.ContentBlockerLoader" UserInfo={NSDebugDescription=connection to service named com.apple.SafariServices.ContentBlockerLoader} #0
And the simpler message is just:
Couldn’t communicate with a helper application.
From what I managed to find (for example here - https://developer.apple.com/forums/thread/756931) the limit for blocking rules should be 150k items.
It was previously 50k but got increased years ago.
Is there anything special I need to do to get the extension to work reliably with say 100k items?
I am usng the JSON format from the docs:
{
"trigger": {
...
},
"action": {
...
}
},
{
"trigger": {
...
},
"action": {
...
}
}
]
My trigger is url-filter and the action is type: block
I was thinking about providing multiple JSON files in attachments property of NSExtensionItem but apparently that is not supported.
Thanks for help!
This post is an effort to draw attention to a regression in Tahoe that has a large impact on our app. This bug was filed during seed 3 but remains open:
FB18869578: Regression: WebView fails to render fonts registered with CTFontManagerRegisterFontURLs or ATSApplicationFontsPath
The gist of it is that WKWebView fails to render text that is styled with a “font-family” that references a font that has been loaded into the app using either the ATSApplicationFontsPath Info.plist key or loaded dynamically with CTFontManagerRegisterFontURLs. The area where the text should be is just blank.
There is more detail and a reproducer in the bug referenced above. We really hope this bug can get fixed before GA.
If anyone else would like to try and reproduce it, you can download a test case from here: https://e3supportuploads.s3-accelerate.amazonaws.com/8739959ce24de40fa462798a532aaa99fbfc9affba4f2a3e71d397f9e30d2604
Topic:
Safari & Web
SubTopic:
General
Thread 0 Crashed:
0 WebKit 0x00000001a1b6bf1c WKMouseDeviceObserver.connectedDeviceCount.setter + 68 (WKMouseDeviceObserver.swift:0)
1 WebKit 0x00000001a1b6bea4 @objc WKMouseDeviceObserver.connectedDeviceCount.setter + 152
2 WebKit 0x00000001a1b6d95c closure #2 in WKMouseDeviceObserver.start() + 80 (WKMouseDeviceObserver.swift:0)
3 WebKit 0x00000001a1b4e3e9 <deduplicated_symbol> + 1
4 WebKit 0x00000001a1b4e139 <deduplicated_symbol> + 1
5 WebKit 0x00000001a1b4e769 <deduplicated_symbol> + 1
6 libswift_Concurrency.dylib 0x0000000196037cdd completeTaskWithClosure(swift::AsyncContext*, swift::SwiftError*) + 1 (Task.cpp:546)