When we wrote about Safari on 13 October, the picture was still being pieced together from a bug report and trade reporting. Since then Apple has spoken. On 19 October the WebKit team published a post titled “Blocking Identity Resolution Infrastructure”, its first public explanation of the block that hit ad tech in September.
For anyone writing 2027 plans, it settles three questions and leaves one open. It also makes the case for a simple habit: give every campaign a line built from the brand and the content.
What Apple has now confirmed
The target is identity resolution. Apple describes third parties that pick up the email address a reader types when logging in or signing up for a newsletter, turn it into a persistent ID and hand that ID back to the page, where it can be used to profile people and target ads across sites. Safari now blocks network access to those services.
The block reaches the Mac. Apple names Safari and WebKit on iOS, iPadOS, macOS and visionOS 27. Earlier reporting documented only iPhone and iPad. On the iPhone every browser runs on WebKit, so the block follows readers into other browsers too.
The block holds at domain level. Apple says changing the structure of a request does not get around it.
Apple names no companies and publishes no list. Trade reporting ties the block to the domains behind UID2, ID5, LiveRamp, Permutive and Audigent.
The Trade Desk is a separate case
The Trade Desk’s ad server was the most visible casualty. Safari blocks whole domains, and its identity endpoint shared a domain with ad delivery. Apple has since removed that domain from the list in an iOS 27.2 beta, while UID2, The Trade Desk’s email-based ID, stays blocked.
Ad delivery through The Trade Desk returns as devices update. The identity layer that made many Safari impressions addressable stays switched off.
What stays open
Apple’s tracking prevention policy says it grants no exceptions to specific parties and may add restrictions without prior notice. Trade reporting describes a much longer list in preparation, covering hundreds of data and ad tech vendors, which Apple could update remotely. Apple has confirmed none of this, and we make no prediction about its next step. The practical point is simpler: an ID-based line depends on a list the buyer cannot see.
Give every campaign a line built from context
Most plans will keep an identity layer where it still works, and they should. What changes is the foundation underneath it. Every campaign now benefits from a line that plans from the brand and the content, because that line reaches the same readers in Safari, Chrome and every app.
It is the part of the plan that holds whatever happens to the next list. It protects reach on iPhone and Mac, keeps delivery consistent across browsers, and gives you a clean comparison against your ID-based lines in the same report.
Three steps for your 2027 plan
- Report Safari as its own line. Split reach, match rate and conversions by browser and OS version, starting from mid-September. A campaign that stopped bidding on Safari traffic still spends its budget and still fills its dashboard. The difference shows up in who it reached.
- Map the identity dependency of every line item. Ask each partner which domains the reader’s device calls during an ad request, what share of your reach relies on an identifier, and how targeting and measurement behave in Safari today.
- Add a context-built line to every campaign. Brief it from the same brand and objective as the rest of the plan, run it alongside your ID-based lines, and compare the two by browser.
How C Wire builds that line
C Wire builds every campaign from the brand outward. BrandDNA and CampaignDNA capture who the brand wants to reach and what the campaign needs to achieve. MatchPersona turns that into agentic personas, then finds the editorial and video moments where each persona spends attention. The Placement Graph profiles and measures inventory across 500+ trusted publishers down to the individual ad unit, so every placement is chosen with the page in view.
The signal is the page itself, so the plan runs the same way in every browser, and the same persona strategy carries across the trusted web and YouTube. You can activate it as a managed campaign, self-service in the Console, as C Wire Curation deals in your own DSP, or through your AI agent.
If you are writing 2027 plans now, send us one brief. We will come back with a context-built line you can add to it.
