News from WWDC26: WebKit in Safari 27 beta | WebKit
News from WWDC26:<br>WebKit in Safari 27 beta
Jun 8, 2026
by Saron Yitbarek, Tim Nguyen, Antoine Quint, Anuj Panta, Ahmad Saleem, Anne van Kesteren, Alex Christensen, Dominic Mazzoni, Aditya Keerthi, Jean Haberer, Karl Dubost, Keith Miller, Youenn Fablet, Lily Spiniolas, Yoel Hawa, Rupin Mittal, Elika Etemad, Jer Noble, Yija Huang, Etienne Segonzac, Kai Tamkun, Shu-yu Guo, Kiet Ho, Nathan Solomon, Chris Dumez, Charlie Wolfe, Joanna Pan, Simon Fraser, Jean-Yves Avenard, Aleksei Marchenko, Mike Wyrzykowski
Contents<br>Customizable Select<br>Animations<br>CSS<br>Scroll Anchoring<br>HTML<br>JavaScript<br>WebAssembly<br>MathML<br>Spatial Web<br>WebGPU<br>Media<br>Web API<br>Rendering<br>WebRTC<br>Web Extensions<br>Networking<br>Storage<br>Editing<br>SVG<br>WKWebView<br>Web Inspector<br>Accessibility<br>Forms<br>Printing<br>Updating to Safari 27<br>Feedback<br>Safari 27 beta is here. Don’t miss our WWDC26 sessions on web technology, including What’s new in WebKit for Safari 27, to go deeper on our work in this release. Now, let’s dig into this beta, packed with 58 new features, 525 fixes and 4 deprecations that will hopefully make your work as a web developer a little easier.
Here’s a sneak peek of the highlights:
After years of anticipation, you can now use customizable to style your form elements to match the rest of your site or app without rebuilding it in JavaScript or sacrificing accessibility.
Scroll anchoring prevents those visual jumps when content loads above the viewport.
WebAssembly JavaScript Promise Integration (JSPI) lets Wasm code participate in the async world of JavaScript.
Transform-aware anchor positioning closes out a major gap in the anchor positioning story.
The :heading pseudo-class, the revert-rule keyword, and the stretch keyword for box sizing all land in CSS.
Subpixel inline layout makes text rendering more precise.
And that’s just the start.
If you look through the lists of features and fixes in Safari 27, you’ll notice that, although there are 58 brand-new features and 525 fixes — the largest pile of fixes in any Safari release in recent memory — most of what is released is not about new things.
Most of this work has been about existing features behaving more correctly, handling more edge cases, and fitting together with other features the way you’d expect. We committed our time to increasing quality — that’s the story of this release and the year that led to it.
A lot of this work was also about aligning to web standards. When we found a spec that was unclear or incomplete, we helped update it, and then updated WebKit to match.
For example, Safari 27 contains 30 SVG fixes, including updates based on recent decisions in SVG 2 where we revived the Working Group. SVG is used on 67% of webpages, making this work very impactful. Anchor positioning continues to get refined as the CSS specification settles. And in more subtle places throughout the release — URL parsing details, event listener options, timezone identifier handling, innerText edge cases — features that look unchanged on the surface now behave the same way in Safari as they do in Chrome, Firefox, and Edge.
We also spent time making sure features still work across different contexts. A :has() selector invalidating properly when siblings change. An aspect-ratio resolving correctly against a percentage height. box-shadow rendering correctly on table-row elements. background-clip: text working on table header elements. Bugs that appear when combining features are among the hardest to find and the most frustrating, but we’ve made significant progress in hunting them down.
If something has been bothering you, test it in Safari 27 beta. You might be pleasantly surprised. And if it hasn’t been fixed yet, file a bug report, or add a comment to an existing issue with a concrete scenario, a link to a real site, or a reduced test case. The more concrete the problem, the more helpful it is.
This work goes beyond the Safari browser. When your customers open their news app, their banking app, their shopping app, there’s a good chance the interface they interact with is powered by the HTML, CSS, and JavaScript that’s rendered by WebKit and JavaScriptCore — the same engines inside Safari. Every fix in this release isn’t just for the browser — it benefits everything the web platform touches.
Let’s dive in.
Customizable Select
Safari 27 beta adds support for customizable , which transforms the element. You can now build a fully custom form element that matches the look and feel of your website or web app, without reaching for a JavaScript library or sacrificing the accessibility, reliability, and native platform integration of a real HTML form control.
Use the new appearance: base-select to clear the native styling and start with a clean palette. Then insert any additional CSS you want to create your custom design. Customizable comes with new pseudo-elements for more granular control, like ::picker-icon to target the disclosure indicator and...