We’re seeing an issue in our Safari Web Extension where not all cookies from the Set-Cookie response header are accessible. We are using macOS 15.4 and Safari 18.4.
In the webRequest.onHeadersReceived callback, the Set-Cookie header returned by Safari only includes some of the cookies set by the server. If multiple Set-Cookie headers are present, we seem to receive only a partial list, some cookies are missing entirely.
In Chrome and Firefox, the same callback provides all cookies set by the server without issue.
We are looking for assistance in fixing these issues and having our Safari Extension function the same as it does in Firefox and Chrome.
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I'm not loving the huge Favorites icons in Safari on MacOS 26, is there a way to reduce the size of them so that we can see more favorites on the list without scrolling down?
How can I make a background image take the entire screen in ios26?
I've tried position fixed, sticky, env() css variables but nothing worked. It does it when in PWA mode, but I would like to do so in the browser too.
Whenever I make a safari view controller on XCode26 Beta 5, there appears to be a blurry white overlay overtop the controller. This worked fine in XCode26 Beta 2, with no code differences.
Anyone have any suggestions?
When I open the browser in Safari on iOS 26, I want to specify the background color for the header notch (where the time, battery, etc. are displayed) and the footer indicator area.
Specifying the theme color in HTML as shown below did not change anything.
<meta name="theme-color" content="#ff0000">
<meta name="theme-color" media="(prefers-color-scheme: light)" content="#ff0000">
<meta name="theme-color" media="(prefers-color-scheme: dark)" content="#ff0000">
The HTML below specifies the background color as green, but is it necessary to specify the background color directly in the body like this?
Or is there some kind of metadata, like theme color?
<!doctype html>
<html lang="ja">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width,initial-scale=1" />
<meta name="theme-color" content="#ff0000">
<meta name="theme-color" media="(prefers-color-scheme: light)" content="#ff0000">
<meta name="theme-color" media="(prefers-color-scheme: dark)" content="#ff0000">
<title>サンプル</title>
</head>
<body style="background:#00ff00">
<main>
<p>テキスト</p>
</main>
<div
id="overlay"
role="dialog"
aria-modal="true"
data-test-id="health-warning-modal"
style="
color:#000000;
position:fixed;
inset:0;
z-index:30000;
background:#2563eb;
display:grid; /* 初期表示：表示中 */
align-items:center;
justify-content:center;
overflow-y:auto;
"
>
<div
style="
padding:60px 16px;
display:flex;
flex-direction:column;
gap:20px;
width:100%;
box-sizing:border-box;
"
>
<p
style="
font-weight:700;
text-align:center;
margin-top:20px;
font-size:28px;
line-height:1.4;
"
>
オーバーレイ
</p>
</div>
</div>
</body>
</html>
After updating to the new iOS, in Safari, my overlays and backdrops using 100dvh no longer cover the full screen there's now a gap at the bottom.
Switching to 100vh fixes it, but that causes scrolling issues on older Safari versions since 100vh includes extra height.
Has anyone else experienced this? What's the recommended fix that works across iOS versions?
We have a SAML-based SSO App Extension that uses WKWebView to load the SAML login request. This implementation has been working correctly on iOS versions prior to 26. However, starting with iOS 26, the extension consistently crashes when calling WKWebView.load(_:).
The crash occurs inside WebKit, specifically in:
/Library/Caches/com.apple.xbs/Sources/WebKit/Source/WebKit/UIProcess/WebsiteData/WebsiteDataStore.cpp
at
WebKit::WebPageProxy::loadRequest(...)
No app-level exception is thrown, and the extension terminates with:
Thread 10: EXC_BREAKPOINT (code=1, subcode=0x1a31dbe00)
It appears that WKWebView initialization or WebsiteDataStore creation is now restricted in extension contexts on iOS 26, but this change is not documented in the SDK release notes. Could you please confirm if this is an intentional sandbox restriction in iOS 26 or a regression in WebKit?
Steps to reproduce:
Implement an App Extension using ASAuthorizationProviderExtensionAuthorizationRequest.
Create a WKWebView instance in the extension.
Attempt to load a SAML login request (POST request with headers).
Observe immediate crash on iOS 26 (works fine on earlier versions).
Expected behavior:
WKWebView should load the request or fail gracefully as in prior releases, without crashing the extension process.
Request:
Please clarify if WKWebView usage inside extensions is officially unsupported as of iOS 26, and if so, recommend an alternative approach for handling SSO flows.
When I'm inspecting a WKWebView in a simulator and the WKWebView loads a local URL with a port number, I've found that most features of Safari dev tools that worked in iOS 17 are broken in iOS 18. Here are the steps I'm taking:
Set up a WKWebView with isInspectable = true that loads a local URL, e.g. https://www.local.mydomain.com:3000
Install a self-signed SSL certificate on a simulator for www.local.mydomain.com
Run my app on the simulator
The WKWebView loads successfully
In Safari on my Mac, I can select the WKWebView and open dev tools to inspect it
If the simulator is on iOS 17, this works fine, no issues.
But if the simulator is on iOS 18, Safari dev tools are mostly broken. I can tell that there is a connection to the WKWebView because the Network tab logs the requests that I expect. But I cannot use any of the other dev tools features: Elements, Sources, Console, etc.
Has anyone else encountered this? Is there a workaround?
Topic:
Developer Tools & Services
SubTopic:
General
Tags:
Xcode
Safari Developer Tools
Safari and Web
Simulator
Hi all,
Chrome has it already - animation-timeline aka scroll-animations.
I can nowhere find any informations on what's the status in Safari/Webkit.
Seems like they do not have it on the agenda at all?
Does anyone know anything - I wanted to push a feature request for that - but also seem there is no feature request list anymore for webkit.
See: https://www.w3.org/TR/scroll-animations/
Cheers and kind regards!
Device: iPhone 15pro, ios26.0 (23A 341)
IOS version: 26.0 (23A 341)
When using position: sticky; bottom: 0, the div is expected to stick to the bottom of the viewport when the browser toolbar hides while scrolling. However, it stops at the height where the toolbar was, instead of moving down with the disappearing toolbar.
In the image below, the red-bordered navigation shows the situation where it does not stick to the bottom.
i
Hello,
I've got Smart App Banner set up on my website. However, I want to be able to measure the traffic coming from this banner to the app store / app (i.e. measure impressions/downloads).
Apple documentation (https://developer.apple.com/help/app-store-connect/view-app-analytics/manage-campaigns/) says you can set up a campaign link and use it in the Smart Banner to track those who download / open the app store page using your smart banner (so that we can get attribution).
However, there is no documentation at all in terms of how this should be added to the tag when implementing a Smart App Banner.
I've tried so many different variations and none have tracked downloads. This includes a structure based on an example taken from WWDC from a few years back which also did not work.
I would appreciate any help!
Hello Apple Developer Community,
I'm experiencing an issue with PDF link interaction in WKWebView that appears to be specific to iOS 26.
Problem Description:
I'm loading a PDF in WKWebView.The links may vary widely and are not necessarily DPF, so I need to load them using WKWebView. On iOS versions prior to 26, links within the PDF are clickable and work correctly. On iOS 26, the same links are not clickable (no response when tapped). Expected Behavior:
PDF links should remain clickable and functional across all iOS versions.
What I've Tried:
Tested opening the PDF directly in Safari on iOS 26 - links still not clickable This suggests the issue might be related to changes in the system's PDF rendering engine Reproduction Steps:
Load the PDF URL in WKWebView Navigate to page 12 Attempt to tap the link Environment:
Test Devices: iPhone 15(26.0 ) / iPhone 16 Pro Max(18.0.1 ) Xcode: 16.2
Questions:
Is this an intentional change in iOS 26's PDF handling or WKWebView? If so, is there a new API or configuration to restore link interactivity?
Any guidance or suggestions would be greatly appreciated!
browser.runtime.onMessage in content script intermittently fails on iOS 18.5 (Safari Web Extensions)
Hi everyone,
I’m encountering a critical reliability issue with message passing in my Safari Web Extension on iOS 18.4.1 and iOS 18.5.
In my extension, I’m using the standard messaging API. The background script sends a message to the content script using browser.tabs.sendMessage(...), and the content script registers a listener via:
browser.runtime.onMessage.addListener(handler);
This setup has been working reliably in all prior versions of iOS. However, after updating to iOS 18.4.1 and 18.5, I’ve noticed the following behavior:
✅ The content script is successfully injected, and onMessage.addListener is registered (I see logging confirming this).
✅ The background script sends the message using the correct tabId (also confirmed via logs).
❌ The content script’s onMessage listener is not consistently triggered.
⚠️ This issue is intermittent, sometimes the message is received, sometimes it is silently dropped.
❌ No exceptions or errors are thrown in either script, the message appears to be sent, but not picked up from the content script message listener.
Summary:
Content scripts injected via manifest continue to receive and respond to chrome.tabs.sendMessage() calls even after the user has navigated away from the original page, causing messages intended for the current tab to be handled by zombie contexts from previous pages.
Environment:
Safari/iOS Version: 18.5
Extension Manifest: Version 3
Expected Behavior:
When a user navigates from Page A to Page B:
Page A's content script context should be destroyed.
chrome.tabs.sendMessage(currentTabId, message) should only reach Page B's content script
Only Page B should be able to respond to action button clicks (or other background to content messages).
Actual Behavior:
When navigating from Page A to Page B:
Page A's content script context persists as a "zombie".
chrome.tabs.sendMessage(currentTabId, message) reaches zombie context instead of the Page B's one. Hence, it looks like the extension is broken because the content script does not respond to the background messages.
Details:
Tab ids are properly recognized by both background and content script
The problem does not always occur; it occurs on random occasions. It's quite easy to have it reproduced.
It can be reproduced easier if user clicks ext icon during site loading (before it fully loaded), triggering ActionClick (ext icon click) event and then sending a msg upon it to the content script
Regardless of whether the content script is injected into the tab using manifest.json, registerContentScripts, or executeScript, the problem is still there
Once the problem occurs, e.g. user is on macys.com but zombie injected content script believes it's google.com (a previous page), even refreshing the tab doesnt change anything - zombie context is still there (thinking it's still google.com) . Changing a domain to something completely different one could help though. Then going back to macys.com could still lead to the described issue.
A zombie content script does not have access to the page's console function and others.
Example communication
Sending following message from the background to the content script using chrome.tabs.sendMessage()
{
"tab": {
"id": 155,
"active": true,
"url": "https://www.macys.com/",
"title": "Macys.com"
}
}
Results in the content-script zombie context response (the url is taken from the window.location.href)
"message": {
"type": "ActionClicked",
"data": {}
},
"response": {
"data": {
"windowUrl": "https://www.google.com/",
"contentReached": true,
"timestamp": "1,753,138,945,272",
}
}
}
I am trying to run JavaScript only after the page has loaded, and according to here - https://developer.apple.com/documentation/safariservices/safari_app_extensions/injecting_a_script_into_a_webpage, I should use DOMContentLoaded. However, it does not seem to work.
This is my content.js file:
function runOnStart() {
document.addEventListener('DOMContentLoaded', function(e) {
document.body.style.background = "rgb(20, 20, 20)";
document.html.style.background = "rgb(20, 20, 20)";
var divElements = document.body.getElementsByTagName('div');
for(var i = 0; i < divElements.length; i++) {
let elem = divElements[i];
elem.style.background = "rgba(255, 255, 255, 0.05)";
}
});
}
runOnStart();
If I take the code outside of the event listener, it runs fine, but a lot of the elements haven't loaded in yet so it doesn't work as it should.
The function is definitely running, but the event listener simply doesn't work. I appreciate any help you can give!
Hi there!
I'm new to App Development and I'm running into the following error when playing audio on a website loaded through a WKWebView:
0x112000cc0 - ProcessAssertion::acquireSync Failed to acquire RBS assertion 'WebKit Media Playback' for process with PID=70.197, error: Error Domain=RBSServiceErrorDomain Code=1 "(originator doesn't have entitlement com.apple.runningboard.assertions.webkit AND originator doesn't have entitlement com.apple.multitasking.systemappassertions)" UserInfo={NSLocalizedFailureReason=(originator doesn't have entitlement com.apple.runningboard.assertions.webkit AND originator doesn't have entitlement com.apple.multitasking.systemappassertions)}
Looking through this forum, it seems more people have this issue, yet no one has found a solution (or posted it...). The solutions that I did find (Background Modes capability, webView.configuration.allowsInlineMediaPlayback = true), did nothing.
To make sure the issue had nothing to do with my own code, I created an empty project to reproduce the issue. I'm not sure on the best way to share it, but it's a small file (forgive me, I have no clue what it does, actually chatGPT made it for me. My real application is a WebApp wrapped with Capacitor, so it handles all the Swift stuff)
import SwiftUI
import WebKit
struct WebView: UIViewRepresentable {
let urlString: String
func makeUIView(context: Context) -> WKWebView {
let webView = WKWebView()
webView.configuration.allowsInlineMediaPlayback = true
webView.configuration.allowsAirPlayForMediaPlayback = true
webView.navigationDelegate = context.coordinator
return webView
}
func updateUIView(_ uiView: WKWebView, context: Context) {
if let url = URL(string: urlString) {
let request = URLRequest(url: url)
uiView.load(request)
}
}
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
class Coordinator: NSObject, WKNavigationDelegate {
var parent: WebView
init(_ parent: WebView) {
self.parent = parent
}
func webView(_ webView: WKWebView, didFailProvisionalNavigation navigation: WKNavigation!, withError error: Error) {
print("Web page loading failed: \(error.localizedDescription)")
}
}
}
struct WebViewDemo: View {
var body: some View {
NavigationView {
WebView(urlString: "https://www.w3schools.com/html/tryit.asp?filename=tryhtml5_audio_all")
.navigationBarTitle("Web View")
}
}
}
struct WebView_Previews: PreviewProvider {
static var previews: some View {
WebViewDemo()
}
}
Nothing special, right?
When I build the app and navigate to a website that has an tag (https://www.w3schools.com/html/tryit.asp?filename=tryhtml5_audio_all). I still see the error when I play the audio.
It plays nonetheless, but the error is there. I'm not at all interested in actually playing audio in the background/when the app is closed/suspended. I just want the error to go away!
I've tried different iOS versions (14,15,16,17), but the problem persists.
Anyone know what's happening?
We are experiencing an issue with Safari in all versions from 18.0 to 18.5 that does not occur in version 17. It affects both iPhones and Macs. And does not happen in Chrome or Windows.
The problem is impacting our customers, and our monitoring tools show a dramatic increase in error volume as more users buy/upgrade to iOS 18.
The issue relates to network connectivity that is lost randomly. I can reliably reproduce the issue online in production, as well as on my local development environment.
For example our website backoffice has a ping, that has a frequency of X seconds, or when user is doing actions like add to a cart increasing the quantity that requires backend validation with some specific frequency the issue is noticable...
To test this I ran a JS code to simulate a ping with a timer that calls a local-dev API (a probe that waits 2s to simulate "work") and delay the next HTTP requests with a dynamic value to simulate network conditions:
Note: To even make the issue more clear, I'm using GET with application/json payload to make the request not simple, and require a Pre-flight request, which doubles the issue.
(async () =&gt; {
for (let i = 0; i &lt; 30; i++) {
try {
console.log(`Request start ${i} ${new Date().toLocaleString()}`);
const res = await fetch(`https://api.redated.com:8090/1/*****/probe?`, {
method: 'GET',
mode: "cors",
//headers: {'Content-Type': 'text/plain'},
headers: { 'Content-Type': 'application/json' },
});
console.log(`Request end ${i} ${new Date().toLocaleString()} status:`, res.status);
} catch (err) {
console.error(`Request ${i} ${new Date().toLocaleString()} error:`, err);
}
let delta = Math.floor(Math.random() * 10);
console.log("wait delta",delta);
await new Promise(r =&gt; setTimeout(r, 1000 - delta));
}
})();
For simplicity lets see a case where it fails 1 time only out of 10 requests.
(Adjusting the "delta" var on the time interval create more or less errors...)
This are the results:
The network connection was lost error, which is false, since this is on my localhost machine, but this happens many times and is very reproducible in local and production online.
The dev-tools and network tab shows empty for status error, ip, connection_id etc.. its like the request is being terminated very soon.
Later I did a detailed debugging with safari and wireshark to really nail down the network flow of the problem:
I will explain what this means:
Frame 10824 – 18:52:03.939197: new connection initiated (SYN, ACK, ECE).
Frame 10831 – 18:52:04.061531: Client sends payload (preflight request) to the server.
Frame 10959 – 18:52:09.207686: Server responds with data to (preflight response) to the client.
Frame 10960 – 18:52:09.207856: Client acknowledges (ACK) receipt of the preflight response.
Frame 10961 – 18:52:09.212188: Client sends the actual request payload after preflight OK and then server replies with ACK.
Frame 11092 – 18:52:14.332951: Server sends the final payload (main request response) to the client.
Frame 11093 – 18:52:14.333093: captures the client acknowledging the final server response, which marks the successful completion of the main request.
Frame 11146 – 18:52:15.348433: [IMPORTANT] the client attempts to send another new request just one second later, which is extremely close to the keep-alive timeout of 1 second. The last message from the server was at 18:52:14.332951, meaning the connection’s keep-alive timeout is predicted to end around 18:52:15.332951 but it does not. The new request is sent at 18:52:15.348433, just microseconds after the predicted timeout. The request leaves before the client browser knows the connection is closed, but by the time it arrives at the server, the connection is already dead.
Frame 11147 – 18:52:15.356910: Shows the server finally sending the FIN,ACK to indicate the connection is closed. This happens slightly later than the predicted time, at microsecond 356910 compared to the expected 332951. The FIN,ACK corresponds to sequence 1193 from the ACK of the last data packet in frame 11093.
Conclusions:
The root cause is related to network handling issues, when the server runs in a setting of keep-alive behavior and keep-alive timeout (in this case 1s) and network timming issue with Safari reusing a closed connection without retrying. In this situation the browser should retry the request, which is what other browsers do and what Safari did before version 18, since it did not suffer from this issue.
This behaviour must differ from previous Safari versions (however i read all the public change logs and could not related the regression change).
Also is more pronounced with HTTP/1.1 connections due to how the keep-alive is handled.
When the server is configured with a short keep-alive timeout of 1 second, and requests are sent at roughly one-second intervals, such as API pings at fixed intervals or user actions like incrementing a cart quantity that trigger backend calls where the probability of failure is high.
This effect is even more apparent when the request uses a preflight with POST because it doubles the chance, although GET requests are also affected.
This was a just a test case, but in real production our monitoring tools started to detect a big increment with this network error at scale, many requests per day... which is very disrupting, because user actions are randomly being dropped when the user actions and timming happens to be just near a previous connection, where keep alive timeout kicks-in, but because the browser is not yet notified it re-uses the same connection, but by the time it arrived the server is a dead connection. The safari just does nothing about it, does not even retry, be it a pre-flight or not, it just gives this error.
Other browsers don't have this issue.
Thanks!
I'm converting a Chrome Extension to a Safari Web Extension, I found it's not easy to get favicon of current tab/url natively.
The tab object in Safari doesn't have favIconUrl.
{
	"id": 121,
	"index": 6,
	"active": true,
	"width": 1324,
	"audible": false,
	"url": "https://github.com/",
	"mutedInfo": {
		"muted": false
	},
	"windowId": 2,
	"title": "GitHub",
	"incognito": false,
	"pinned": false,
	"height": 935,
	"highlighted": true,
	"status": "complete"
}
		
2. I didn't find Safari has similar thing like chrome://favicon
3. I found Safari's favicon caches in ~/Library/Safari/Favicon Cache/favicons but have no idea how to use them in Safari Web Extension.
I’m experiencing a crash in WKWebView on iOS 26 Developer Beta 5 and Beta 6 with the following exception:
CALayer position contains NaN: [nan 65]
The crash occurs when the following CSS properties are applied to content displayed in WKWebView:
-webkit-user-select: none;
-webkit-touch-callout: none;
This issue happens consistently whenever these styles are set, leading to the crash inside WKWebView.
Is this a known bug in the current iOS 26 betas, or is there a recommended workaround?
I'm experiencing a Safari Web Extension issue where the non-persistant background script seems to crash after 30 seconds even when the content script is messaging it.
Here is a minimal-reproducible example. When running in an emulator, the background script will stay responsive forever. However, when running on a physical device, the background script becomes non-responsive after 30 seconds of activity. It never becomes responsive again until I toggle the extensions enable/disable toggle, after which it stays active for 30 seconds and then crashes again.