Safari Preview Build 256 Ships Fixes Across Engine
Developers get an early look at changes to CSS, JavaScript and WebGL before they reach the stable Safari release.
Updated on Nov. 5, 2026 in Software
Apple has released Safari Technology Preview 256, a test build of its browser that includes fixes and updates across a wide range of web platform areas. It runs alongside the standard Safari browser and can be downloaded without a developer account. This is a shipped preview build, not a final consumer release of Safari itself.
Why it matters
Safari Technology Preview is Apple's channel for showing work-in-progress browser engine changes before they reach the mainstream Safari release. Apple's stated aim is to gather feedback from developers and users on its browser development process, which makes each numbered preview a window into where WebKit-based browsing is heading.
The release notes list fixes and updates across Accessibility, Animations, CSS, Editing, Forms, HTML, JavaScript, Media, Networking, Rendering, SVG, Security, Web API, Web Extensions, Web Inspector, WebGL and WebRTC, but the extraction gives no per-item benchmark figures. The one hard number is the build designation 256, and the complete changelog is published on the Safari Technology Preview website.
The details
Safari Technology Preview is a separate build of Apple's browser that installs next to the regular Safari app, so developers can test pages against upcoming engine behavior without replacing their daily browser. Updates are delivered through the Software Update mechanism in System Preferences or System Settings to anyone who downloaded the preview from Apple's website. The current build is compatible with macOS Tahoe and macOS Golden Gate.
Timeline
March 2016 — Safari Technology Preview is first introduced.
November 4, 2026 — Safari Technology Preview 256 is released.
The Tech Race
Apple's preview program places it alongside other browser vendors who publish experimental builds to test engine changes before mainstream release. Build 256 continues Apple's own numbered preview track, which has run since March 2016 and remains the channel for surfacing WebKit work ahead of stable Safari.
Anyone who downloaded Safari Technology Preview from Apple's website can receive this build through Software Update in System Preferences or System Settings, with no developer account required. The preview runs alongside regular Safari, so users who want to try upcoming changes can do so without losing their everyday browser.
The takeaway
Watch the complete release notes on the Safari Technology Preview website for which of the 17 listed areas changed in behavior. Items that stabilize in preview builds tend to reach mainstream Safari later, so the notes are the best early signal of what Safari will do next.
Further reading
For broader context on how these builds fit into the app ecosystem, see the Software section.
