The story. Server-side ad calls are ad tech’s answer to Safari blocking identity domains, and Digiday says the Google remedies ruling adds a second effect: Prebid may get the final say in the auction. (Digiday, 3 November 2026)
01What happened
- Safari is blocking identity domains. Digiday reports that with iOS 27, Safari has begun blocking domains tied to identity resolution providers, including The Trade Desk and ID5, that link browsing to email addresses.
- Ad tech is moving calls server-side. Companies and IAB Tech Lab are pushing ad calls off the browser, including through Tech Lab’s Trusted Server technology.
- The remedies ruling opens a door for Prebid. In Digiday’s reading, Google’s ad exchange would have to bid into Prebid’s server, instead of Google’s ad server having the final say on the winning bid.
- Reporters disagree on how much this wins. Digiday’s Seb Joseph called Trusted Server “almost a panacea” and warned that Apple will likely target other mechanisms too. Ronan Shields said ad tech cannot take control from firms that own the browser, the phone OS and the cloud.
- Google may not fight for it. Shields noted that Google’s 28 October earnings showed its third-party display network business, the GAM area, underperforming again, and suggested Google will not lose sleep if Prebid takes it.
02What it means inside a GAM network
Earlier pieces on this desk covered Safari’s blocks and the days big publishers need to move identity server-side. The new item is the order of the auction. Today most GAM publishers run Prebid in the page and pass its winning bid to Google’s ad server, which decides. Digiday describes a flip, with Google’s exchange as one bidder inside Prebid’s server.
For a publisher that would change who sees the price pressure. Header bids would no longer need to beat a Google price floor line by line, and unified pricing rules would matter less. It would also move work from ad ops, who tune line items, to whoever runs the server-side stack.
Two cautions. This rests on Digiday’s description of a ruling and a podcast discussion, and the remedy’s timing and form can still change. And server-side calls do not by themselves restore the identity Safari removed.
Safari pushes ad calls server-side, and the Google ruling may put Prebid in charge of the auction.
03What publishers should do about it
04The bottom line
Safari pushes ad calls server-side, and the Google ruling may put Prebid in charge of the auction. Both change who controls the decision. A publisher that knows its current auction setup will be able to act on either quickly.