Google has a new plan for replacing browser cookies with ‘Topics API’

Google has a new plan for replacing browser cookies with ‘Topics API’

You probably won't like it any better than FLoC

Browser cookies, especially cross-domain cookies, make it easy to track people across the internet and collect data for targeted advertisements. That’s why many browsers now block third-party cookies, from Firefox to Vivaldi, and Google has been trying to build a replacement that addresses some privacy concerns. The company’s first attempt didn’t work out well, so Google is trying again with Topics API.

Mozilla, Vivaldi, Brave, and other browsers had no plans to implement FloC.

Google’s first attempt at replacing cookies was announced in August 2019 as the “Privacy Sandbox.” The first implementation was the Federated Learning of Cohorts, or FLoC for short, which shifted the responsibility of tracking away from cookies and third-party ad networks to the browser. The technology grouped together people with similar browsing histories, then allowed advertisers to target those groups of people (the “cohorts”) without most of the personally-identifiable information that cookies usually provide. Google started testing FloC in Chrome last year.


FloC was slightly better than third-party cookies, but it was not popular with many privacy advocacy groups and companies. The Electronic Frontier Foundation (EFF) criticized Google for rolling out FloC to millions of Chrome users before possible privacy risks were full addressed, and DuckDuckGo advised people to turn off FloC (and updated its browser extension to block all FloC tracking). Mozilla, Vivaldi, Brave, and other browsers had no plans to implement FloC, while Apple and Microsoft took a “wait and see” approach.

Topics API illustration

Third-party cookies vs Topics API (Source: Google)

Google announced on Tuesday that it is replacing the FLoC proposal with a new technology, called the Topics API. Similar to the earlier FLoC design, it uses your browser to locally generate groups that advertisers can target, but now it’s based on specific topics instead of grouping people that share an interest in multiple topics together. Here’s how Google explains it:

With Topics, your browser determines a handful of topics, like “Fitness” or “Travel,” that represent your top interests for that week based on your browsing history. Topics are kept for only three weeks and old topics are deleted. This process happens entirely on your device without involving any external servers, including Google servers. When you visit a participating site, Topics picks just three topics, one topic from each of the past three weeks, to share with the site and its advertising partners. Topics enables browsers to give you meaningful transparency and control over this data, and in Chrome, we’re building user controls that let you see the topics, remove any you don’t like, or disable the feature completely.

Even though the new technology might be an improvement over FloC, it likely won’t be much more popular. The Topics API relies on your web browser to generate the topics you are interested in, based on your browsing history, essentially turning Chrome itself into an advertisement targeting platform. That’s slightly better than third-party cookies sending buckets of user data to advertisers, but still isn’t privacy-respecting.

Google declined to confirm if the final implementation of the Topics API would be opt-in or opt-out for Chrome users, and the company also didn’t say if it has already discussed the standard with other browser vendors. Google Chrome has somewhere around 50-60% market share in the browser market (and around 70% on mobile), so Google could push ahead without Microsoft or Apple on board, but that could give more ammunition to anti-competitive lawsuits and fines.

About author

Corbin Davenport
Corbin Davenport

Corbin is a tech journalist and software developer. Check out what he's up to at

We are reader supported. External links may earn us a commission.