The story. Should identity infrastructure move server-side? For large publishers, probably yes, and quickly; for small ones that outsource ad ops, not on their own. After Apple’s Safari block, ID5 is shifting more of its identity infrastructure off the device. (Digiday; AdExchanger, 29 October 2026)
01What happened
- ID5 is moving server-side. CEO Mathieu Roche told Digiday that going server-side is more resilient because the vendor is no longer on the device. ID5 is testing with selected publishers, and broader rollout is early.
- The blocked list is long. In live tests Digiday saw in the week of 19 October, iOS 27 affected Audigent, ID5, LiveRamp, Permutive and The Trade Desk.
- Impact so far is small. Permutive said only a few customers were hit and moved them to an interim fix. Several sources told Digiday that low iOS 27 adoption has produced more talk than measurable disruption.
- Size decides the effort. Roche said larger organisations could finish the technical work in days rather than months. Smaller publishers that outsource ad operations would find it harder.
- The framework exists. IAB Tech Lab’s Trusted Server Framework, introduced in March 2025, runs server-side ad requests, Prebid Server integration and edge processing on publisher-operated infrastructure.
- The doubts are real. Critics cite added complexity, dependence on cloud providers and possible fingerprinting. Some worry publishers could build and then see Apple restrict the new path too.
02What it means inside a GAM network
Server-side moves the identity call from a third-party browser domain to a domain the publisher controls. That is why Roche says the device cannot block it. It does not change what Google Ad Manager sees in the auction; it changes where the ID is resolved before the request is sent.
For a publisher on GAM with a Prebid wrapper, the work sits in the header-bidding layer and the DNS and hosting setup behind it. A team with engineers can do that. A publisher whose ad ops sit with a vendor will pay for it through that vendor, which is the cost warning Digiday’s sources raised.
The limit on the evidence: Apple has not said how it will treat server-side calls, and Digiday’s questions to Apple went unanswered. Reading the move as durable is a bet. That is APH desk analysis.
Server-side is a sensible hedge for publishers with engineers and a poor bet to buy blind for those without.
03What publishers should do about it
04The bottom line
Server-side is a sensible hedge for publishers with engineers and a poor bet to buy blind for those without. Check how much of your traffic is actually affected before paying to fix it.