Sec-Browsing-Topics
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
Warning: This feature is currently opposed by two browser vendors. See the Standards positions section for details of opposition.
Note: An Enrollment process is required to use this feature in your applications.
The Sec-Browsing-Topics request header sends the selected topics for the current user along with the associated request, which are used by an ad tech platform to choose a personalized ad to display.
If the calling site does not have the Topics API included in a successful privacy sandbox enrollment process, attempting to create or modify Sec-Browsing-Topics fails silently, and any existing Sec-Browsing-Topics header is deleted.
See Using the Topics API for more details.
| Header type | Request header |
|---|---|
| Forbidden header name | yes (prefix Sec-) |
Syntax
Sec-Browsing-Topics: <array-of-observed-topics>
Directives
A JSON object representing an array of up to three objects representing the current user's selected topics for the last three epochs. Each object contains the following properties:
configVersion-
A string identifying the algorithm (other than the model part) used to calculate the topic.
modelVersion-
A string representing the model used to classify a string (such as a web page's hostname) into topic IDs.
taxonomyVersion-
A string representing the taxonomy version used.
topic-
A number representing the ID of the topic, which can be used by the browser to retrieve the topic from the taxonomy (see an example taxonomy of interests).
version-
The
configVersion,modelVersion, andtaxonomyVersion, concatenated with colons (:) between each.
Examples
The exact property values may vary by browser implementation. An example header from Chrome might look as follows:
Sec-Browsing-Topics: [{configVersion: "chrome.1", modelVersion: "1", taxonomyVersion: "1", topic: 43, version: "chrome.1:1:1"}]
Specifications
This feature is not part of an official standard, although it is specified in the Topics API Unofficial Proposal Draft.
Browser compatibility
BCD tables only load in the browser