Category taxonomies value 3 means IAB Tech Lab Ad Product Taxonomy 1.0

When to send it

Value 3 selects Ad Product Taxonomy 1.0, which classifies what an ad sells (alcohol, gambling, pharmaceuticals and so on) rather than what a page is about. It fits the ad-side fields: BidRequest.bcat and BidRequest.acat through BidRequest.cattax, and a creative's Bid.cat through Bid.cattax.

When both sides classify against the ad product taxonomy, a buyer can apply a seller's blocklist exactly instead of mapping content categories onto advertisers. The value is confused with 8 (Ad Product Taxonomy 2.0); the versions are separate files, so name the one your IDs came from. Using 3 in Site.cattax or Content.cattax is a mismatch, since those fields describe content.

Example

{
  "app": {
    "cattax": 3
  }
}

Fields that carry it

• app.cattax
• seatbid.bid.cattax
• cattax
• app.content.cattax
• app.content.gtax
• app.content.producer.cattax
• app.publisher.cattax
• site.cattax

Other values in category taxonomies

The category taxonomies list page explains the whole list and its common mistakes.