Safari 27 Released: Customizable Select, Scroll Anchoring and What Site Owners Should Test

Apple released Safari 27 on September 14, 2026. According to Apple's Safari 27 release notes, it is available for iOS 27, iPadOS 27, visionOS 27, macOS 27, macOS 26 and macOS Sequoia. On September 17, 2026 the WebKit team published its detailed write-up, WebKit Features for Safari 27.0.

Safari is the browser on every iPhone and iPad, so a Safari release changes what a large part of your audience sees, whether or not you planned for it. For teams doing front-end development, this release removes some long-standing workarounds. For site owners, it also includes a few behavior changes and removals worth testing.

Below is a plain-English summary of what shipped, what could affect an existing site, and what to do about it.

What shipped in Safari 27

The WebKit post says the number of features in the release grew from 58 in the first beta in June to 83 in the final version, and it reports 844 resolved issues. The beta was first described in WebKit's WWDC26 post on June 8, 2026.

Everything described in this article is in the released version, not a preview. The headline items in WebKit's post are customizable select menus, scroll anchoring, the model element for 3D content on more Apple platforms, several CSS additions, WebAssembly and JavaScript engine work, a Safari MCP server for developer tooling, and new APIs for apps that embed web content.

Customizable select menus

The dropdown menu, the select element in HTML, has been hard to style for as long as the web has existed. Designers who wanted a branded dropdown usually asked developers to rebuild it from scratch in JavaScript, which costs time and often damages accessibility and keyboard support.

WebKit's post explains that Safari 27 supports customizable select: a developer applies the CSS value appearance: base-select, and the native dropdown becomes fully styleable and can hold richer content. It is opt-in, so existing dropdowns keep their current look unless your CSS asks for the new mode.

The practical effect, in our view, is that custom dropdown components become less necessary over time. A native control that can be styled is usually cheaper to maintain and more accessible than a hand-built replacement.

Scroll anchoring: fewer page jumps

Most people have experienced a page that jumps while they are reading because an image, ad or banner loaded above the text. WebKit's post says Safari 27 now supports scroll anchoring, which adjusts the scroll position so the content stays where it was when something is inserted above it. WebKit states that developers do not need to do anything to enable it.

This is one of the few changes that applies to existing sites automatically. It should be an improvement almost everywhere. The exception worth testing is a page with its own custom scroll logic, such as chat windows, infinite feeds or scripts that correct scroll position manually, where two corrections could now interact.

3D, CSS and engine improvements

WebKit reports that the model element, previously limited to visionOS, is now available on iOS, iPadOS and macOS. It lets a page embed an interactive 3D model with an HTML element, which is relevant to product pages in retail, furniture and similar catalogs.

On the CSS side, the post lists the stretch keyword for sizing, a :heading pseudo-class that matches h1 through h6, the revert-rule keyword, and anchor positioning that is aware of transforms. On the engine side it lists WebAssembly JavaScript Promise Integration (JSPI), a standards-compliant rewrite of the JavaScript module loader, and the Service Worker static routing API, which lets a site declare rules so that some requests bypass the service worker.

WebKit also describes a Safari MCP server, which gives AI coding agents access to the page's DOM, network requests, screenshots and console output. That is a developer tool, not something visitors see.

Changes and removals that could affect existing sites

New features are optional. Removals are not. WebKit's post lists several items that were removed or changed in Safari 27:

• SVG: the SVGLocatable and SVGTransformable interfaces, the nearestViewportElement and farthestViewportElement properties, the viewTarget property on SVGViewSpec, and the glyph-orientation-horizontal property were removed.
• MathML: the href attribute is deprecated on all MathML elements except the a element.
• CSS anchor positioning: the default value of position-anchor changed from auto to normal, and the anchors-valid and anchors-visible keywords were renamed to anchor-valid and anchor-visible.

Most business websites will not use any of these. The sites to check are those with interactive charts, maps or diagrams built on older SVG libraries, technical or educational content using MathML, and newer interfaces that adopted anchor positioning early for tooltips and popovers. WebKit also reports 66 SVG fixes in this release, so SVG-heavy pages may render slightly differently, usually for the better.

What it means for your business

The points in this section are our guidance, not statements from Apple. For a typical marketing site or online store, Safari 27 is a low-risk update: pages should feel steadier thanks to scroll anchoring, and nothing in the removal list is commonly used in ordinary page templates.

The opportunity is in future work. If a redesign or new build is planned, customizable select and the newer CSS features may let your team drop some JavaScript components. That decision depends on whether the other browsers your customers use support the same features, so ask your developers to check current support before removing a fallback.

If you have a mobile app that displays web content inside it, note that WebKit's post also lists new WKWebView APIs for app developers. Hybrid apps and in-app browsers on iOS use the same engine, so teams doing iPhone app development should run their web views on iOS 27 as part of regular release testing.

What to do next

Test your key journeys, such as sign-up, checkout, search and any dashboard, on a device running iOS 27 and on a Mac with Safari 27. Remember that Safari 27 is also offered on macOS 26 and macOS Sequoia, so desktop users will receive it without upgrading their operating system.

Pay particular attention to pages with charts or diagrams, long pages where content loads late, and custom scroll behavior. If your analytics show a change in Safari conversion or error rates after September 14, 2026, start the investigation with those areas. Finally, ask your team whether any custom dropdowns are due for replacement, and add that to the backlog rather than treating it as urgent.

Conclusion

Safari 27, released on September 14, 2026, is a large release: 83 features by WebKit's count, led by customizable select menus and scroll anchoring, alongside a short list of SVG, MathML and anchor positioning changes that can affect older or specialized pages. Most sites need only a round of testing.

If you do not have Apple devices on the latest software to test with, or you find something that looks different, get in touch and we can help you check it.