How Index sends Privacy Sandbox topics in bid requests

Google's Topics API provides the functionality to include interest-based user information in bid requests using something called topics without the use of cookies in Chrome when publishers are integrated with Index using Prebid.js An open-source library for publishers to implement header bidding on their websites and manage multiple header bidding partners. version 8.9.0 or later. The topics are selected from an advertising taxonomy based on the IAB Audience Taxonomy.  When provided, Index sends the following topic information in the user.data.ext and user.data[].segment objects in the bid requests that we send to DSPs.

Note: Index will start sending these fields in December 2023.

Field	Type	Description
user.data.name	String; required	The exchange-specific name for the data provider that observed the topic IDs. If Index observed the topic IDs, the name will always be topics.indexexchange.com.
user.data.ext.segclass	String; required	The taxonomy version of the taxonomy specified in the segtax field, for example "taxonomy_v2" Taxonomy V1: https://github.com/patcg-individual-drafts/topics/blob/main/taxonomy_v1.md Taxonomy V2: https://github.com/patcg-individual-drafts/topics/blob/main/taxonomy_v2.md
user.data.ext.segtax	Integer; required	The ID associated with the taxonomy specified in the IAB Interactive Advertising Bureau (IAB). An advertising business organization that develops industry standards, conducts research, and provides legal support for the online advertising industry. Tech Lab in Enumeration of Taxonomies. Index supports the following taxonomy for the Topics API for Privacy Sandbox:
user.data.segment.id	String; required	The ID is the topic ID mapped to the version specified in the segclass field.

 

The following shows what topic data looks like in a bid request An OpenRTB request that is sent from a supply-side platform (SSP) or ad exchange to the DSP requesting a bid response for potential impressions. A bid request contains information about the impression that allows the DSP to decide whether to bid on the impression.:

{
    ...
    "user": {
        "data": [{
        "name": "topics.indexexchange.com", // Exchange-specific name for the data provider that observed the topic ID
                "ext": {
                    "segtax": 600, // Taxonomy Mapping to V1
                    "segclass": "1" // Model Mapping
                },
                "segment": [{
                    "id": "10"// Topic ID
                }]
            },
            {
                "name": "topics.indexexchange.com", // Exchange-specific name for the data provider that observed the topic ID 
                "ext": {
                    "segtax": 601, // Taxonomy Mapping to V2
                    "segclass": "2" // Model Mapping
                },
                "segment": [{
                    "id": "12" // Topic ID
                }]
            }
        ]
    }
}

For more information, refer to the Topics Integration Guide for SSPs.