Safari's vertical tabs: more than convenience

For years, one of the most persistent complaints about Safari has been a feature gap rather than a security flaw: tab management that scales poorly once a session sprawls past a dozen windows. Apple's latest developer betas address that gap directly, and tucked alongside the headline tab change are two other additions — Adaptive Dark Mode and expanded Siri access to page content — that touch how much of a browsing session is rendered and how much of it an assistant can read. According to TechRadar's reporting, all three arrive in the first developer builds of iOS 27.3, iPadOS 27.3 and macOS 27.3, alongside watchOS 27.3 Dev Beta 1.

Vertical tabs land in dev betas

The centerpiece, per TechRadar, is vertical tabs. Safari users can open the Safari View Menu or go into Settings to switch to a vertical layout. The tabs sit on the left side of the browser window in iPadOS and macOS, and also on iOS for the iPhone Duo — the foldable form factor the report refers to by that name.

By default the tabs appear as icons rather than full labels, a space-saving choice. Hovering over an icon surfaces a quick look at the hidden browser window behind it. The feature set also includes the ability to pin tabs at the top of the list by dragging and dropping, plus tab groups. TechRadar reports that the tabs work on iPad and on the iPhone Duo in both portrait and landscape orientation.

The report is candid that Apple is not first here. TechRadar's Lance Ulanoff notes he began using vertical tabs in Microsoft Edge years ago, and that Chrome recently added them as well. Safari's version arrives on a browser that, while trailing Chrome globally, is the default for Apple's 2.5 billion customers.

Adaptive Dark Mode reaches unsupported pages

The second addition changes what Dark Mode can do. Historically the setting only applied to pages that shipped their own dark styling; everything else stayed bright. Adaptive Dark Mode extends the treatment to pages that don't support it, with Apple promising the result won't ruin the sites.

Mechanically, per the report, the feature automatically darkens light backgrounds, inverts logos and graphics, recolors vector artwork, lifts raised surfaces, and detects shadows and adjusts them. Sites that are already darkened are left alone. Developers get new tags they can use to prevent Adaptive Dark Mode from adjusting their pages — a control that matters for anyone whose brand presentation depends on exact color rendering.

Siri reads beyond the visible frame

The third change concerns how much of a browsing session Siri can see. Siri AI already has, with user permission, awareness of what is on screen. With this update, according to TechRadar, it will see entire web pages beyond what fits in the screen frame, and even hidden tabs.

The report frames the capability around organization tasks: sorting every tab related to a trip to Malta by activity, or grouping car-shopping tabs by price. Siri AI can also, through new Custom Actions, clean up browsing history by topic, site, and time period. TechRadar offers the example of hiding a stretch of shopping on a particular site for a gift.

That is a meaningful expansion of what an assistant parses during ordinary browsing — from the visible viewport to the full contents of pages and tabs the user isn't currently looking at. The source describes the permission model as unchanged in principle (Siri acts with the user's permission) but does not detail how the broader page access is scoped or limited.

The wider 27.3 feature set

TechRadar lists several other items shipping in the same developer beta wave across iOS 27.3, iPadOS 27.3, macOS 27.3 and watchOS 27.3 Dev Beta 1:

• Siri App Actions, which let Siri AI organize files, make trip plans, create playlists, schedule group messages, and find photos to share.
• An Apple Health app overhaul using Apple Intelligence to surface more insights from health data.
• Two Audio Intelligence features for the Apple Watch Series 12: Live rewind, which requires a double-press of the watch crown to read back the last snippet of conversation, and Siri Recap, which when enabled uses Apple Intelligence to summarize an entire talk, speech, lesson, or similar recording.

The browser changes are the part of this package most directly tied to how people interact with the open web, but they ship as one bundle with the assistant and wearable features above.

Betas first, release date unset

None of this is in customers' hands yet. TechRadar reports the changes are coming to the 27.3 betas first and will eventually roll out to other platforms in a full release. For now they are found only in the Dev Betas, which the report describes as typically the earliest and potentially buggiest builds before Apple moves to Public Betas that anyone can install and then to final releases.

There is no word on when the full releases will arrive. TechRadar cautions against installing developer betas on everyday Apple devices — standard advice for pre-release builds, and relevant here given that Safari is the default browser on those devices.

What the permission model leaves open

For security-minded readers, the most consequential item in this batch isn't the tab layout. It's the expansion of Siri's page access. A browser extension or assistant that can read hidden tabs and full page contents has a wider view of a session than one limited to the visible screen — which is precisely the kind of access that matters when a user is logged into email, banking, or internal tools in background tabs.

The source does not describe any new consent prompt, scope limit, or per-site control for the expanded page access. It states only that Siri AI operates with the user's permission. Whether that permission covers hidden tabs by default, or is requested separately, isn't addressed. Readers evaluating the feature should treat that as an open question until Apple documents it.

Adaptive Dark Mode raises a smaller but concrete point: the developer opt-out tags exist because recoloring logos, inverting graphics and adjusting shadows can alter how a page presents itself. Sites that rely on precise visual rendering — authentication prompts, payment pages, certificate warnings — are exactly where a browser-side restyling layer deserves scrutiny.

Why the tab change matters beyond convenience

Vertical tabs are unlikely to move any security needle on their own. But the packaging is instructive: a long-requested usability feature arrives in the same beta as an assistant that reads more of your browsing session and a rendering layer that restyles pages without the site's involvement. Each is a modest change; together they shift how much of the browser's state is processed by Apple's software rather than left to the page.

For IT and security teams managing Apple fleets, this suggests a familiar cycle: developer betas now, public betas next, full release on a timeline Apple hasn't stated. The window to evaluate how the expanded Siri page access behaves — and whether the permission model is granular enough for regulated environments — falls inside that gap. That evaluation is worth doing before the features reach production devices, not after.