Safari 27.3 beta introduces vertical tabs, adaptive dark mode, and Siri AI custom actions

Apple has released the first developer betas of iOS 27.3, iPadOS 27.3, macOS 27.3, and visionOS 27.3, bringing significant updates to the Safari web browser. The most prominent addition is the support for vertical tabs, a long-awaited feature that rearranges open tabs along the left side of the window rather than horizontally at the top. This space-efficient design maximizes webpage content visibility while making it quicker to scan full tab titles. The feature can be enabled through the settings, and works across all devices including the iPhone Duo's larger display.

Another notable addition is the adaptive dark mode, which addresses websites that lack native dark mode support. When users browse to sites with bright backgrounds while in dark mode, Safari now offers a “Try” button to preview a darker version before enabling it permanently. The feature uses Apple Intelligence to analyze individual sites, automatically darkening light backgrounds, adjusting text contrast, and inverting logos and graphics as needed. Users can enable the feature automatically or manage it site-by-site. Both features represent substantial improvements to the browsing experience that have been frequently requested by the user community.

For devices supporting Apple Intelligence, Safari 27.3 beta also introduces enhanced Siri AI capabilities with custom actions. Building on Siri's existing screen awareness, the update grants visibility into entire web pages beyond the visible screen frame, as well as hidden tabs. This enables wholesale organization tasks, such as grouping tabs by topic or cleaning up browsing history filtered by site and time period. The features are available to developers starting today, with Apple expected to release the public version of iOS 27.3 and companion operating systems by early December following additional beta testing rounds.