Topics API

The Topics API is a retired Chrome feature that let a site's ad tech ask the browser for a few broad interest topics, inferred from recent browsing, to target ads without third-party cookies.

Topics replaced Google's earlier FLoC proposal. Chrome worked out a user's top topics each week from a fixed list, based on the sites visited. It then returned up to three of them, one per recent week, to callers that had seen the user on sites about those topics. The aim was to give advertisers interest signals while keeping the browsing history on the device.

Adoption stayed low, and Google listed Topics among the ten Privacy Sandbox technologies it retired on 17 October 2025 (Google, 17 October 2025). Chrome then followed its normal removal process. The intent posted on 7 November 2025 planned deprecation in Chrome 144 and removal in Chrome 150. In June 2026, with usage at 4.9% of page loads, the owners proposed replacing the code with a stub in Chrome 152 and switching it off through a staged field trial.

On 24 September 2026 the trial had reached 1% of Chrome Stable, version 153 and later, with no known breakage and usage at 2%. Chrome's API owners then approved moving to 10% and to 100% after 15 October 2026 (blink-dev, 24 to 30 September 2026). Whether the rollout had reached all users by 9 November 2026 could not be confirmed.

Example: A publisher that called document.browsingTopics() to add topics to its bid requests should expect the call to be rejected in Chrome and should fall back to contextual signals and first-party data. The Chrome owners noted that scripts must already handle such rejections, because the API could be disabled for many reasons (blink-dev thread).

Related terms: Privacy Sandbox, CHIPS, contextual targeting, third-party data, consent string.

Authoritative source: Chromium blink-dev, "Intent to Deprecate and Remove: Topics API" (thread opened 7 November 2025).

Read the full guide: Identity after the Privacy Sandbox.