Apple published a blog post explaining why WebKit now blocks the technology adtech companies use to track people across websites. The ad industry is bracing for less reach and higher prices, and Apple's policy says it may add restrictions without prior notice if a party tries to circumvent its tracking prevention.
Apple published a blog post late on Monday defending new restrictions that block technology used to identify and track consumers across websites. The changes run through WebKit, the browser engine that powers Safari and other browsers on iPhones and iPads.
Apple targets identity resolution
Apple said the change targets "identity resolution," a method adtech companies use to connect data points such as email addresses, phone numbers, IP addresses and browsing history to track users across devices. The method grew popular as browsers, including Safari, began phasing out third-party tracking cookies.
However, Apple argued that users might readily hand over an email address to log in or join a newsletter, but most wouldn't expect it to be shared with other companies for invisible tracking. The post also says Apple is implementing "domain-level" blocking so identity providers can't get around the restriction by changing how they send data.
Earlier this month, Apple began blocking domains operated by several companies that offer alternative identifiers, without warning. The blocked domains included The Trade Desk, LiveRamp, ID5, Permutive and Audigent. Apple then rolled out a fix a few days later that restored The Trade Desk's ad-serving domain.
Advertisers brace for less reach
The ad industry is now bracing for impact as more users update to iOS 27. Industry insiders said advertisers expect less reach, higher prices for the audiences they can still identify, and more difficulty measuring whether campaigns worked.
An academic paper that analyzed 600,000 websites over 41 months found that 83.76% of those sites were using alternative identifiers by May 2025. If advertising becomes less effective on the open web, marketers could shift more budget to walled-garden platforms like Meta and Google.
Apple signals more restrictions
Apple has also created a broader block list that can dynamically block potentially hundreds of adtech, martech and data companies, as first reported by AdExchanger. Affected companies may not realize they were added until they begin experiencing disruptions.
Apple's tracking-prevention policy makes clear it won't allow workarounds. According to Apple's policy: "we may add additional restrictions without prior notice" if a party attempts to circumvent its tracking prevention methods.
Source: Business Insider
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