Developing
Apple made no concession and gave no explanation. It is unknown whether the production release changes the blocking.
In 60 seconds
- The Trade Desk filed WebKit bug 324771 on September 21, 2026 about requests to nine domains being blocked in Safari.
- On October 5 Apple's John Wilander asked for a test of a new iOS 27.2 beta; The Trade Desk said it would test and report back.
- The blocklist includes adsrvr.org and identity domains such as uidapi.com, id5-sync.com and permutive.com.
- Publishers are showing renewed interest in IAB Tech Lab's Trusted Server.
Impact Layer
- What changed
- Safari's blocking of some ad and identity domains is now in an open bug report with a test build attached.
- Why it matters
- If identity and delivery domains are blocked on iPhone and iPad, addressable ads and measurement on Safari can fail without a visible error.
- Who is affected
- Ad tech vendors, publishers and advertisers with Safari traffic.
- Martech stack area
- Advertising, Data
- Stack impact
- Check Safari delivery and match rates against other browsers, and watch the iOS 27.2 release notes.
- Business impact
- Moderate Based on PPC Land's reading of the public bug report. Whether the production iOS 27.2 build changes anything, and whether macOS is affected, is not known.
- Related technologies
- Related vendors
- What to watch
- The Trade Desk's test result, and the iOS 27.2 release.
The Trade Desk’s senior director of engineering filed WebKit bug 324771 on September 21, 2026, and on October 5 Apple’s John Wilander replied that a new iOS 27.2 beta had shipped and asked him to test it, according to PPC Land’s reading of the report. The reply came 15 minutes after the post; the engineer said his company would test and report back. Apple made no concessions and gave no explanation.
The blocked domains
The report lists nine domains: tainted.example, uidapi.com, adsrvr.org, id5-sync.com, eu-1-id5-sync.com, rlcdn.com, pippio.com, permutive.com and ad.gt. Eight relate to identity services; adsrvr.org is The Trade Desk’s core delivery domain. The mechanism cited is WebKit PR 58670, “Unconditionally block requests going to certain domains”, added in February. The bug lists iPhone and iPad only.
Publisher response
IAB Tech Lab’s Trusted Server, launched in March 2025, is drawing renewed interest, with its product lead reporting “a big influx of publishers” (no number given). Paradium, which publishes Men’s Journal and Parade, is routing Permutive through it.
Our read
The open questions are whether build 24B5099f changes the blocking, whether it reaches the production release and whether macOS is affected. Until then, compare Safari delivery and match rates with other browsers so a drop shows up in your own numbers.
Sources
- PPC Land: Apple asks The Trade Desk to test an iOS 27.2 build that may unblock ads (opens in a new tab)
Source of the bug report, dates, blocked domains and publisher reactions.