Apple Confirms Safari Block on Identity Resolution Firms

Apple confirmed on Oct. 19 that Safari now cuts off network access to identity resolution companies, formalizing a blockade that broke The Trade Desk's ads and five identity vendors' services when the latest iPhone software update landed last month.

The confirmation came in a blog post, ending weeks of silence. Apple described the targets as identity resolution companies — firms that stitch together separate scraps of data about a person, such as email addresses, phone numbers, IP addresses, browsing history and device information, to recognize and track them across sites and devices.

The industry noticed the damage before Apple explained it. When the latest iPhone software update arrived in September, The Trade Desk's ads stopped loading in Safari. Investigators then worked out that ID5, LiveRamp, Permutive, Audigent and UID 2.0 were blocked as well.

The outcomes have since diverged. The Trade Desk received a reprieve, according to the source report. The identity vendors did not. Apple stayed silent on the distinction while the industry spent Advertising Week New York guessing at the company's motives.

What does the block actually hit?

The affected companies occupy the connective tissue of programmatic advertising (the automated buying and selling of ad space). Their business is matching fragmented signals — an email here, an IP address there — into a persistent view of one person that advertisers can target and measure against.

Safari's network-level cutoff denies those firms the connections that make that stitching possible. Apple's framing, per its blog post, targets the tracking itself rather than any single vendor.

The named casualties span the category:

• ID5, an independent identity alternative built for the post-cookie market
• LiveRamp, whose RampID is a widely used identifier for data matching
• Permutive, a publisher-side data platform
• Audigent, a data and identity company
• UID 2.0, The Trade Desk's open-source identifier, though The Trade Desk's own ad serving has resumed

How expensive is the fallout?

Nobody can yet say how far the damage spreads, the source report notes, and the early fallout already looks expensive for a lot of companies. Apple's blog post did not quantify the scope of the block, name every affected vendor, or explain why The Trade Desk was spared.

Those gaps matter. Without a published list of blocked domains or criteria for exemptions, vendors and their publisher clients cannot tell whether the reprieve is temporary, negotiated, or accidental. Apple has not said whether further software updates will widen the cutoff.

What happens next?

Apple has now put its position in writing, which gives the ad tech sector a concrete policy to respond to rather than rumor. The open questions — the size of the revenue at risk, the durability of The Trade Desk's reprieve, and whether other browsers follow — will decide whether this is a contained outage or a structural break in the identity supply chain.