Simile negli intenti a Chrome Canary, Safari Technology Preview è una versione di Safari per sviluppatori web, con funzionalità sperimentali — le cose che abilita sono elencate in questa pagina del sito di Apple.
Dal blog di WebKit:
Safari Technology Preview is a standalone application that can be used side-by-side with Safari or other web browsers, making it easy to compare behaviors between them. Besides having the latest web features and bug fixes from WebKit, Safari Technology Preview includes the latest improvements to Web Inspector, which you can use to develop and debug your websites. Updates for Safari Technology Preview will be available every two weeks through the Updates pane of the Mac App Store.