demo · v144

Auction Replay

Protected Audience ran a sealed, on-device auction between many bidders for a single ad slot — without revealing the user’s interest groups to the publisher. This replay shows what that auction looked like step by step, beside the contextual replacement most ad partners are moving to. So you can see what disappears.

Protected Audience (formerly FLEDGE) is removed in Chrome 144. The replay below is illustrative — navigator.runAdAuction will throw. The contextual lane runs against live signals you can audit.

runAdAuction: checking…

before (PA on-device auction — removed)

interest groups joined off-page bid against each other inside the browser; publisher never sees the group.

click run auction

after (contextual — pre-bid)

SSP sends page signals to bidders, server-side; no per-user interest groups in the loop.

click run auction

the API

// before (in-browser auction, removed)
const winner = await navigator.runAdAuction({
  seller: "ssp.example",
  decisionLogicURL: "https://ssp.example/decide.js",
  interestGroupBuyers: ["dsp-a.example", "dsp-b.example"]
});
adFrame.src = winner;  // opaque fenced-frame URL

// after (contextual pre-bid, server-side)
const { ad, bid } = await fetch("/prebid", {
  method: "POST",
  body: JSON.stringify({ url, topic, floor })
}).then((r) => r.json());
adFrame.src = ad;

see also