The story. Publishers are now testing IAB Tech Lab’s Trusted Server, an open-source setup that runs ad calls from servers the publisher controls, as a way around Apple’s Safari blocklist. The idea dates from March 2025, and few acted on it until Apple’s iOS 27 change. (Digiday, Apple’s Safari ad tech blocklist sends publishers back to IAB Tech Lab’s Trusted Server, 8 October 2026)
01What happened
- Interest jumped this week. Rowena Lam, senior director of privacy and data at IAB Tech Lab and product lead for Trusted Server, says a big influx of publishers asked about it or committed to testing. She declined to give a number.
- First go-live is close. Tech Lab is getting ready to launch with its first publisher, with results to share soon.
- How it works. Today Safari lets a page contact dozens of ad tech companies directly, and it blocks any on Apple’s list. Trusted Server moves those calls to publisher servers, which Safari cannot see.
- A first test is under way. Paradium, owner of Men’s Journal and Parade, moved its Permutive code to run through Trusted Server. It is watching whether audience data flows again on Safari.
- It is not the only route. Aditude’s Justin Wohl says its Prebid Server can process ad requests outside the browser and connect to ID5, UID2 and LiveRamp.
02What it means inside a GAM network
Earlier pieces here covered the block itself and Apple’s ability to edit the list remotely. The new fact is that a workaround is being tested in the open. The mechanism matters for anyone running Google Ad Manager with Prebid: the browser stops being where bidders and identity vendors are called.
The catch is revenue. Digiday notes that publishers who moved auctions to their own servers earned less, because buyers lost the cookies they used to recognise readers and bid lower. Server-side calls can restore addressability, but they do not by themselves restore the signals buyers pay for.
Paradium’s Stephanie Mazzamaro, head of revenue and data, draws the line. Trusted Server should help ID longevity, ad-block resilience and clean auction data. Viewability, verification and getting buyers to accept the numbers is where most of the work remains.
One limit on the evidence: no publisher has reported results yet. Paradium is still testing, and Tech Lab’s first live publisher has not been announced. Nothing here shows a recovered Safari CPM.
Apple's list turned Trusted Server from a someday project into a live option.
03What publishers should do about it
04The bottom line
Apple’s list turned Trusted Server from a someday project into a live option. It can keep vendors reachable on Safari, but buyers will bid on measured results, so test on a slice and compare before moving revenue.