Google's Topics API Proposal: What Marketers Need to Know.

04 March 2022 min PoV

Google announced its new online advertising solution, Topics API. The privacy sandbox will replace Federated Learning of Cohorts (FLoC).

In short:

  • Google Chrome is phasing out cookies between mid to late 2023
  • FLoC has been retired, and Topics API is Google's new proposal to replace third-party cookies
  • Topics API allows partner sites and ad partners to receive only the topic segment, thus creating a more privacy-friendly targeting capability
  • There are currently 350 topics available and that list will grow over time
  • 5 topics per browser will be stored within the designated 3-week period.
Google Topics API. An illustration of a group of consumers shopping in a mall.

What is the Topics API? 

Google's Topics API is the latest method being tested to sustain advertiser targeting capabilities when the use of cookie-based identifiers will be retired in late 2023.

The Topics API replaces Google's previous privacy solution, "Federated Learning of Cohorts (FLoC)", which created groups of users based on interests and attributes and will instead store up to 5 "topics" within the user's browser from the past 3 weeks.

How does the Topics API differ from the cohort approach?

 The core difference between the information shared via FLoC compared with Topics is that the FloC method passed a cohort (or grouped) ID, whereas Topics API offers the partner site and ad partners to receive purely the Topic segment itself - creating a far more private targeting capability.

These topics are curated based on segments like "Health & Beauty", “Books and Literature”, and “Food and Drink”, and will be stored for 3 weeks. Users will be able to have transparency over which ones they have been assigned, and have the ability to opt-out of ones they wish not to be targeted based on.

This storage window exceeds the previous one week that FLoC offered, and moves away from the fingerprinting method of identification, which posed the potential to isolate and expose individual user data via browser information.

Currently, there are 350 available topics, and that list will grow over time. This will increase the amount of advertiser targeting options and improve relevancy. Sensitive topics are automatically excluded to mitigate the risk of brand safety issues and empower users to have control over their browser behaviours.

How will Topics API work?

5 topics per browser will be stored within the designated 3-week period. The most relevant segment will be chosen for the end-user based on their most recent interests and behaviours online.

The data is stored on the user’s device, rather than relying on external servers. This aims to increase the relevancy of targeting to an end-user opposed to a potentially diluted pool of options from the cohort design.

Will browser adoption affect Topics API?

It is a certainty that browser adoption was also a limiting factor for previous solutions like FLoC, with competing browsers not showing immediate enthusiasm to onboard the features within their own systems.

However, as this is a Google product, Chrome will of course, be a sure bet and is the dominant browser in Australia with the largest market share.

With Chrome holding the lion’s share of the market, this could still be a powerful tool for advertisers, helping to retain some of the targeting granularity they have become accustomed to, however with ever-increasing privacy measures in the market, the pressure is on for advertising platforms, and their tools, to retain efficiency and scale.

Is Topics API better than FLoC?

There have been some questions raised about the collected data and relevancy. Whilst this extended period of surfacing data from the user’s browser history could benefit advertisers with a longer user journey, for faster-moving goods or services, the information could become rapidly irrelevant and therefore be potentially limiting for some advertisers.

Additionally, certain topics may pose a higher propensity for users to opt-out of targeting, such as gift seeker within the “Shopping/Flowers” topic segment – particularly where devices/browsers are shared within a household.

The Topics method also relies on a website that has opted into the API to be able to match the interest/behaviour of the user to the targeted product/service. Topics are determined within the end user’s browser, on their own device, and then mapped to the website structure of an opted in partner site based on the domain and subdomain information.


  • Transparency & control - allows users to view and manage opt-ins of topics, enhancing privacy and control over ads being shown to you
  • Privacy safe – a shift away from fingerprinting enhances user security
  • User browser level storage - allows for relevant targeting in a privacy-safe environment
  • Brand safety - sensitive topics are automatically excluded

  • 3-week storage window and limited number of topics in storage could potentially be quick to become dated for some faster-moving advertiser models/UX
  • Shared devices - browser level topic storage could cause advertising waste and poor targeting relevancy on shared household devices
  • Adoption - browser and partner adoption of the Topics API relies on opt-in

What should marketers do to prepare for Topics API?

As the digital world prepares for a world without cookies, increasing scrutiny is placed on advertising efficiency and maintenance of scale to audiences. What remains a constant is the importance of measurement when planning for a sustainable advertising strategy.

Since the announcement, there have been some concerns from advertisers who are worried about the lack of granularity for targeting. It is important to keep in mind that we are a while away before Topics API is launched, and the list of included topics will grow over time.

As Topics API is in its early stages, there will be further developments as the privacy sandbox becomes realised. Google announced Topics API in late January 2022, and while there haven’t been any major changes at this time, there have been some minor updates to the Chrome Developers Guide.
Right now, it is best to wait and see what happens with Topics API. It is still in its infancy and is yet to be put to the test, like where we were with FLoC not so long ago.
In the meantime, it is a fantastic opportunity to reassess your targeting solutions to ensure they are browser-agnostic, adaptable and privacy-focused.

Contact Resolution Digital

Our remarkable team have been providing digital solutions to clients in Australia for over 15 years. We are a trusted long-term partner for many clients, from start-ups to large, listed businesses. Get in touch with the Resolution Digital team.

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