Google Topics API: What is it, and how does it work?
5 min read
Amid rising privacy concerns, Google is phasing out third-party cookies. However, websites that depend on revenue from targeted advertising still need to show relevant ads. So, as part of its Privacy Sandbox initiative, Google developed the Topics API. But what is it, and how does it work?
Table of Contents
Table of Contents
What is Google Topics API?
Google Topics is an application programming interface (API) designed to replace third-party cookies for targeted advertising. The Topics API categorizes a user’s interests by analyzing the types of websites they visit. Websites and advertisers use this data to deliver personalized, interest-based ads.
Google Topics API: How does it work?
Google Topics monitors your browsing activity to identify topics you’re interested in, even if you use Google dorks. The domain name of each website you visit determines the site’s topic. For example, a recipe website would belong to the “Food & drink” topic.
The Topics interface monitors your browsing activity in one-week periods called “epochs.” At the end of each epoch, the interface calculates your top five topics. One of these topics is then randomly chosen to represent that epoch. The API only stores data about your interests from the last three epochs.
Third-party advertisers that use the Topics interface are known as API callers. When a user visits one of their websites, these advertisers ask Topics API for information about the user’s topics. The advertiser then uses this data to display a targeted ad relevant to the user’s interests.
However, API callers can only access your data if your listed topics are relevant to their websites. A website carrying the advertiser’s code needs to have previously observed a listed topic within the past three weeks.
What are the main tasks of Topic API?
Google’s Topics API has two main tasks. It aims to give users more privacy and prevent data from being shared with more entities than necessary. It also gives you more control over what Google knows about you. The interface’s other main task is to continue to support targeted advertising.
How are topics curated and selected?
The Topics interface uses a classifier model to sort websites into different topics. These topics are curated in a taxonomy. When you visit multiple websites under the same topic, the interface infers that you are interested.
The taxonomy contains a list of hierarchical categories that each represent a topic. Each category also includes several subcategories. For example, “Food & drink” is a major category, while “Recipes” is one of its subcategories.
When developing the interface, Google only wanted advertisers to see data about a user’s interests. As such, the interface excludes sensitive categories like ethnicity, gender, or sexual orientation.
How many Google topics are there?
Currently, Topics API’s taxonomy contains approximately 469 individual topics. Google initially curated these topics by matching a website’s domain name to a relevant topic. Many of these topics were human-curated, although Google also used machine learning.
How is the Topics API different from third-party cookies?
One of the major aims of Google’s Privacy Sandbox initiative is to phase out third-party cookies. Websites using third-party cookies tracked user activity across multiple websites, even if the sites weren’t related. Internet cookies also collect detailed browsing history data, severely compromising user privacy.
Compared to third-party cookies, Google’s Topics interface gives users more privacy and control over their data. Although the interface tracks user activity, it only collects data on the user’s interests. It doesn’t accumulate in-depth data on a user’s internet history. The interface also allows users to control their topics or opt out of the system altogether.
How does the API reduce fingerprinting?
Browser fingerprinting collects information about a device’s software and settings. Third parties then use this information to gather even more data about our browsing behaviors. However, the API is designed to reduce browser fingerprinting.
Each topic in the API’s taxonomy has many users, making it difficult to identify individuals. When API callers request information about a user’s topics, the interface only selects topics the caller’s websites have recently observed.
The rate at which the API collects data about a user’s topics also helps reduce browser fingerprinting. A user’s topics are updated weekly, with information only available for the past three weeks. These measures make it difficult to identify individual users beyond their recent interests.
What happened to FLoC?
Google developed the Topics interface to replace its previous Federated Learning of Cohorts (FLoC) system. FLoC was designed to monitor recent browsing history and match it to a “cohort.” This cohort was a group of other users who looked at similar websites. Each cohort had a FLoC ID, which advertisers could use to show users personalized advertising.
However, FLoC suffered from several problems. FLoC was designed to preserve privacy but strengthened Google’s monopoly on user data. FLoC was also vulnerable to device fingerprinting. For example, a user’s FLoC ID could be linked to their IP address, compromising user privacy.
Topics API and FLoC both attempt to give users more privacy. However, the API does a better job of this because it identifies users based only on their interests. Unlike a FLoC ID, your interests can’t be linked to your IP address or used for device fingerprinting.
How does the Topics API affect different market players?
The introduction of Topics API impacts various online groups. Let’s look at how the API affects users, publishers, and advertisers.
Users
Google’s API gives users greater privacy when browsing online than third-party cookies or FLoC. It does this by only allowing API callers to see user topics previously observed by the caller’s websites. The interface also gives users more control over which of their topics are shown.
Publishers
Many publishers are uncertain about how Topics API will impact their advertising. It also seems that the broad nature of API topics will benefit larger publishers rather than smaller websites. Having such broad topics also reduces the accuracy of targeted advertising, which may affect ad revenue.
Advertisers
Advertisers will still be able to show users personalized ads using Topics API. The interface also helps with retargeted ads. However, personalized ads may become less specific unless advertisers acquire more first-party data, requiring user consent and more effort from advertisers.
What does a cookie-free future look like?
Google designed its Privacy Sandbox initiative with a cookie-free future in mind. Any replacement for third-party cookies needs to deliver targeted ads without endangering user privacy. Cookies are set to be fully depreciated in 2025. However, publishers and advertisers may still have concerns about moving away from them. As such, Google will probably conduct more industry testing.
How to enable Chrome Topics API
As a publisher, you can turn on Chrome Topics API by following these steps:
- Sign in to your Google Ad Manager page.
- Click “Admin.” Select “Global settings” followed by “Network settings.”
- Go to the “Ad preference settings” section and click “Enable Chrome topics data.”
How to disable Chrome Topics API
If you’re a user and want to disable Chrome Topics API, follow these steps:
- In your Chrome browser, click on the three vertical dots on the far right of the browser.
- Click “Settings.” Select “Privacy and security” followed by “Ad privacy.”
- Click “Ad topics” to see if the Topics interface is active. If so, click on the toggle to disable the feature.