Safari vertical tabs and Adaptive Dark Mode are in Apple’s Safari 27.3 beta, according to the Safari 27.3 beta release notes dated November 3, 2026. They arrived alongside the iOS 27.3 beta 1 developer build. If your tab bar turns into a row of unreadable slivers by mid-afternoon, one of these is aimed at you. The other targets the white page that lights up your face at night. Both are beta features for now, and early hands-on reports disagree on which devices get what.
TL;DR: Apple’s Safari 27.3 beta release notes list a Vertical Tabs layout and an Adaptive Dark Mode for sites that lack a dark theme. Hands-on reports differ on which iPhones get vertical tabs and where the dark mode works. Treat both as beta features that could change before Apple ships them to everyone.
What Safari vertical tabs actually change
Apple’s notes describe Vertical Tabs as “a new vertical layout for navigating and managing tabs with a space-efficient design that maximizes webpage content.” In plain terms, your tabs move to the side of the window instead of sitting in a strip across the top.
9to5Mac’s hands-on says the tabs show as icons by default, and you can drag the bar wider to read full page titles. On Mac and iPad it sits in the View menu, and on iOS 27.3 beta 9to5Mac points to the Settings app.
The trade is easy to see. A top strip gives each tab about the width of a thumbnail once you pass a dozen, while a side list keeps titles readable. That layout also pairs better with wide screens than with narrow ones.
How Adaptive Dark Mode works on bright pages
Apple says Adaptive Dark Mode “automatically adapts bright web pages that don’t natively support dark mode.” That covers the older sites that ignore your system theme and still flash full white at midnight.
In 9to5Mac’s hands-on, a “Try” button appears when Dark Mode is on and a site has no dark theme. Tapping it builds a dark version of the page, and you can have it apply automatically or choose site by site.
Automatic conversion usually has rough edges on photos, logos and charts, and Apple has not said how well it handles them. That is the part worth testing before trusting it.
Who gets these features in the beta
Apple’s notes say Safari 27.3 beta is available for iOS 27.3 beta, iPadOS 27.3 beta, visionOS 27.3 beta, macOS 27.3 beta, macOS 26 and macOS Sequoia. The entries for the two features do not say which devices get which.
Early coverage does not line up. 9to5Mac describes Adaptive Dark Mode on iPhone, iPad and Mac, while Gizmodo reports that on the iPhone side only the iPhone Duo gets vertical tabs, and that Adaptive Dark Mode is limited to macOS.
Both cannot be right, and a first beta is exactly where scope shifts between builds. If a feature is missing on your phone, that may be the build rather than a bug.
What to do before these reach everyone
If you run the beta, try vertical tabs with the tab count you really live with, not three. That is where the layout either earns its place or does not.
If you stay on the public release, there is nothing to change yet. For most people this will be invisible until the day a pile of tabs finally becomes readable.
