iOS 9 offers developers access to an API that can block content such as images, cookies, and pop-up ads in Safari, possibly laying the groundwork for third-party ad blockers.
In particular, developers can create app extensions that supply a JSON file to Safari, which screens incoming Web content without feeding browsing history back to the extension. Xcode in fact includes a template for such extensions, only requiring developers to edit the JSON file to add triggers and actions.
The Safari menu in iOS 9 Settings now includes an option for enabling and disabling individual content blockers. This could allow apps that would block ads, cookies, and offensive content in iOS. While users, especially those with children, might appreciate this, advertisers are sure to be upset at this threat to their mobile income revenue stream.
AppleInsider notes that the content blocker appears to only affect the Safari browser, so it likely won’t interfere with in-app ads, such as those delivered by Apple’s own iAd system.
OS X El Capitan, which also had a beta version seeded to developers on Monday, will also allow third-party content blockers in Safari. Both iOS 9 and El Capitan should be available for free download sometime this fall.