What is a topic?

A topic, in the Topics API, is a subject a user is interested in as evidenced by the websites they visit.

Topics are a signal to help ad tech platforms select relevant ads. Unlike third-party cookies, this information is shared without revealing further information about the user themself or the user's browsing activity.

The Topics API allows third parties, such as ad tech platforms, to observe and then access topics of interest to a user. For example, the API might suggest the topic "Fiber & Textile Arts" for a user who visits the website knitting.example.