Ad Tech's Server-Side Escape From Apple Meets a Hard Ceiling

Apple's Safari has begun blocking domains tied to identity resolution providers such as The Trade Desk and ID5 under iOS 27, and ad tech's answer is to leave the browser entirely.

The industry, together with IAB Tech Lab (the standards body for digital advertising infrastructure), is pushing ad calls server-side (meaning the transaction happens between companies' own computers rather than inside the user's browser), including through Trusted Server, a technology that would limit the browser's control over ad tech firms' actions. Digiday's executive editor of news Seb Joseph and senior ad tech reporter Ronan Shields discussed the shift on the Digiday Podcast, recorded ahead of the Digiday Programmatic Marketing Summit in Nashville, Dec. 1–3.

The immediate trigger is concrete. Safari now blocks the domains of firms that link people's browsing to their email addresses — the core of identity resolution (the practice of matching a person across websites and devices). The remedies ruling in Google's ad tech antitrust trial has opened a second front: Prebid (the open-source header bidding framework publishers use to solicit competing bids) could effectively flip the programmatic auction, so that Google's ad exchange bids into Prebid's server rather than Google's ad server holding final say on the winning bid.

Can Trusted Server outrun Apple?

Joseph is blunt about the technology's limits. "From the conversations we're having in the initial aftermath of the Safari crackdown, Trusted Server has been seen as almost a panacea," he said. "And yet it does feel like that is a misappropriation of what Trusted Server was designed for, and that any attempt to truly lean on it as a durable workaround to what Apple is doing misses the point entirely."

His reasoning: Apple will not stop at the companies it has already targeted. "Whether it's happening via Safari or via Trusted Server, Apple does not want that stuff happening to its customers in any guise and will by hook or crook find a way to offset that," Joseph said. What the source does not say is how quickly Apple could extend blocking beyond Safari, or whether Trusted Server's architecture would survive such a move.

Can ad tech take control?

Shields answers with a flat no. "Can ad tech wrest back control from these power brokers of Apple and Google? I would say absolutely no. They can't wrest control because Google and Apple own the browser, the mobile OS — in the case of Google — they own the ad tech platform and the cloud infrastructure as well," he said. Trusted Server offers at most partial relief: ad tech companies "can gain a degree of autonomy, but they need to behave themselves with it to retain that autonomy."

That behavioral caveat is the article's sharpest point. Joseph asked whether the industry must "get its shit together and do more than the bare minimum, the baseline set by regulators, in order to instill some sort of trust" — because otherwise browsers and platforms "will find a way to put their hand on the scale moving forward." When Shields questioned how realistic self-policing is, Joseph countered: "I'd say it was pretty realistic this time around, because otherwise what happens?"

What does Google's antitrust loss actually cost it?

Shields points to Google's Oct. 28 earnings as evidence the company may not fight Prebid's ascendancy hard. The one aspect of the business that "didn't do well again" is the third-party display ad network business, the GAM (Google Ad Manager) area. "I think they're OK with letting it go. So Prebid wants it? Yeah, fine, go ahead. I don't think they're going to lose too much sleep over it," Shields said.

If that reading holds, ad tech's server-side shift buys autonomy from a weakened gatekeeper in Google's case — and only a temporary reprieve from an emboldened one in Apple's.