Apple’s Safari Technology Preview is a stable test platform for users and devs

Over the last two or three years, Apple has put an increasingly large amount of its software development out in the open. Early betas of OS X and iOS updates, once locked behind a developer paywall and a bunch of nondisclosure agreements, are now released for the public to download and try out. Swift, Apple's new programming language, is now open source. And today, the company is releasing the first of many Safari Technology Preview builds, a new development snapshot of the browser designed to show off more features while offering more reliability and stability than the nightly WebKit browser builds.

Apple will validate Safari Technology Preview builds for two weeks to verify and improve stability, and the company will sign and validate the software and update it through the Mac App Store (the nightly version uses its own built-in updater). Practically speaking, the biggest benefit of the software signing is that you can sync iCloud data with the Technology Preview, making it easier to use the browser as a daily driver and really kick the tires. Google and Mozilla have offered official developer channels for beta and alpha versions of Chrome and Firefox for a long time now, and it's nice to see Apple following suit.

The Technology Preview offers several new features that are included in the nightly builds of WebKit but not in the stable version of Safari. It offers "one of the most complete implementations of ECMAScript 6," the latest version of the standard behind JavaScript; the B3 JIT JavaScript compiler, a new compiler described specifically for JavaScript; a "revamped IndexedDB implementation that is more stable and more standards compliant;" and support for Shadow DOM.

The Safari Technology Preview should be available for download now at Apple's developer site, and it's available to all OS X El Capitan users regardless of whether they have a standard OS X and iOS developer account. There are currently no plans to extend a similar preview to iOS devices, though Safari's built-in "responsive design mode" is intended to approximate different iDevices for testing purposes.