Apple’s latest software update has turned a long-deferred ad tech project into a deadline. Safari is now blocking companies that track users across the web for ad targeting, and publishers say the impact is already showing up in their programmatic revenue.
Why Safari’s blocklist hits hard
When a reader opens a news site in Safari on an iPhone or iPad, the page usually calls out to dozens of ad tech vendors, sharing data and running auctions in the browser. Apple can now cut off any vendor on its own unpublished list. Publishers that rely on blocked vendors are seeing bids drop, and some are already linking the change to revenue dips.
The immediate casualty is premium mobile inventory. Safari is the default on every iPhone and iPad, so it carries a disproportionately valuable slice of readers, especially the audiences advertisers pay more to reach. Losing tracking there hits the most lucrative traffic first.
Trusted Server: the fix publishers put off
The renewed focus is on IAB Tech Lab’s Trusted Server, an open-source set-up that moves ad auction logic off the reader’s device and onto servers the publisher controls. Instead of the phone talking to dozens of vendors, it talks to one domain, while the server handles the rest. Apple can’t block what it can’t see, short of blocking the publisher’s site entirely.
First unveiled in March 2025, Trusted Server had few takers until now. Rowena Lam, senior director of privacy and data at IAB Tech Lab, said interest has accelerated sharply:
Certainly, in this week, we’ve seen a big influx of publishers reaching out to get a better understanding of Trusted Server and or committing to deploying it to test.
Tech Lab says its first publisher will go live soon, with results expected shortly after.
What early adopters are learning
Paradium, which owns Men’s Journal and Parade, already had a head start. It relied on Permutive, one of the blocked vendors, and has now updated its code to run through Trusted Server. Stephanie Mazzamaro, head of revenue and data at Paradium.AI, expects uneven results:
In practice, that should help some signals much more than others, such as ID longevity, ad-block resilience, and clean auction data. Viewability, verification, and getting buyers to accept our numbers are where most of the work remains.
That split matters because server-side delivery can preserve identity and auction data signals better than it solves measurement and buyer trust. Publishers testing it should watch both sides of that ledger.
The bigger market risk
Apple isn’t just a browser. Justin Wohl, vp at Aditude, framed it as an operating-system change rather than a browser change, with implications for Android and Google too. A vendor can go dark with a single list update, no notice, no appeals process.
The backdrop: Apple Ads has been expanding, and the company’s Services division, which houses advertising, hit a record $30.7 billion in the June quarter. That leaves publishers with a hard question:
- Can you run your own auction infrastructure without the old cookie-based addressability?
- Will buyers accept publisher-side numbers for viewability and verification?
- Is the real cost of doing nothing another silent list update that cuts off a key vendor?
What marketers should do now
Advertisers and publishers don’t need to wait for the full picture. Map every vendor in your stack that Safari could block. Test Trusted Server or a server-side alternative with a single segment. Monitor auction, viewability and buyer-acceptance metrics before rolling out further.
Source: Digiday
