The block that started it
Apple’s Safari on new iPhones and iPads began refusing to load requests to certain advertising domains. One of them was adsrvr.org, The Trade Desk’s core ad request and delivery domain. That meant its ads stopped loading inside Safari pages.
WebKit bug 324771, filed by Ian Meyers of The Trade Desk, reproduced nine blocked domains, including Unified ID 2.0, ID5, LiveRamp, Permutive and Audigent endpoints. Safari accounted for 15.1% of global browser traffic in Q3 2025 versus 66.3% for Chrome, according to Cloudflare data cited in PPC Land’s coverage.
Katsur’s pitch: go server side
IAB Tech Lab CEO Anthony Katsur used three X posts from September 30 to October 9 to push Trusted Server, the organisation’s open-source edge runtime. His argument landed in one line:
“It is time to move the entire open web ad stack server side.”
Instead of the browser loading third-party JavaScript from each ad-tech domain, a publisher-controlled reverse proxy sits at the edge and makes those calls server to server. Safari’s browser-level domain check does not see the onward requests.
Katsur declared Trusted Server “production ready TODAY!” and said publishers can “restore addressability and measurement signals in restricted environments” while protecting privacy.
What the repo actually shows
The project’s GitHub repository, captured on October 10, tells a more cautious story:
- 343 commits, 130 branches and 13 contributors.
- Apache 2.0 licence, but no published releases or tags.
- Documentation built from a rolling main branch that “may describe unreleased behavior.”
That does not mean it cannot run in production; open-source infrastructure sometimes ships from main. But a publisher engineering team evaluating production readiness would usually want a version number to pin, release notes and a deployment reference. None of those appear in the capture.
Why this matters for your stack
The cost is not the licence. It is the hosting: Trusted Server runs on Fastly Compute, Cloudflare Workers, Akamai’s Spin or a self-managed container. Every page and ad request passing through an edge runtime is billable traffic. “Free to all” covers the code, not the infrastructure.
Server-side also does not answer every Apple lever. PPC Land has reported that Safari 27 beta blocked some LinkedIn and Bing tracking endpoints by IP address, which means a first-party domain forwarding to blocked destinations can still be exposed. And Trusted Server only addresses web inventory, not in-app iOS monetisation.
What to do next
If Safari is a meaningful slice of your audience, start with an inventory. Trusted Server’s CLI includes ts audit generate https://publisher.example, which inspects a live page and drafts a start config instead of forcing ad ops teams to list every script by hand.
Treat the migration as a pilot. Katsur himself, replying to a question about adoption, described the next step as “testing the framework” — eighteen months after the project launched.
Source: PPC Land
