Site.cattax

Names the taxonomy used by Site.cat, Site.sectioncat, and Site.pagecat, as a value from the AdCOM Category Taxonomies list. When it is absent, value 1 (IAB Content Category Taxonomy 1.0) applies. Added in OpenRTB 2.6.

CurrentintegerOptionalSince 2.6-202204

Field facts

Path: site.cattax
Object: Site
Type: integer
Default: 1
Requirement: Optional
Added: OpenRTB 2.6-202204
Values: AdCOM list Category Taxonomies
Spec section: 3.2.13

How it is used

Content taxonomies are the meaningful choices for a site: 1 and 2 for Content Category Taxonomy 1.0 and 2.0, 5 and 6 for Content Taxonomy 2.1 and 2.2, 7 for 3.0, and 9 for 3.1. The ad product and audience taxonomies in the same list do not describe a site. Values of 500 and above are reserved for vendor taxonomies agreed with the buyer. The type column only gained the default of 1 in 2.6-202309, but the description has said 1.0 is assumed since the field was added.

Allowed values

Value	Meaning
`1`	IAB Tech Lab Content Category Taxonomy 1.0: The original IAB content categories with codes like IAB1-1; deprecated, but still the default when `cattax` is omitted.
`2`	IAB Tech Lab Content Category Taxonomy 2.0: Content Taxonomy 2.0, the first version with numeric IDs; deprecated in favor of later releases.
`3`	IAB Tech Lab Ad Product Taxonomy 1.0: Categories for the product or service an ad promotes, used for ad blocking and creative labeling.
`4`	IAB Tech Lab Audience Taxonomy 1.1: Audience Taxonomy 1.1, which describes people (demographics, interests, purchase intent) rather than content or ads.
`5`	IAB Tech Lab Content Taxonomy 2.1: Content Taxonomy 2.1, a 2.x revision suitable for content classification.
`6`	IAB Tech Lab Content Taxonomy 2.2: Content Taxonomy 2.2, the newest 2.x version in this list.
`7`	IAB Tech Lab Content Taxonomy 3.0: Content Taxonomy 3.0, the first release of the 3.x generation.
`8`	IAB Tech Lab Ad Product Taxonomy 2.0: Ad Product Taxonomy 2.0, the newer of the two ad product versions in this list.
`9`	IAB Tech Lab Content Taxonomy 3.1: Content Taxonomy 3.1, also the default taxonomy for `Content.genres` when `Content.gtax` is absent.
`500+`	Vendor-specific codes: Vendor-specific taxonomies, such as an exchange's own category codes, agreed between the parties.

Example

Where the field sits in a payload, with everything else left out:

{
  "id": "req-1",
  "site": {
    "cattax": 7
  }
}

Common mistakes

Assuming BidRequest.cattax also covers site categories. It applies to the request-level block and allow lists; Site has its own field, which still defaults to 1.

Version history

Added in OpenRTB 2.6-202204, and present in the latest snapshot. The table shows how each version's spec text types the field.

Versions	Type in the spec	Required	Deprecated
2.6-202204	Added in the first 2.6 release, published without a structured text archive; the 2.6-202210 republication is the first tagged text.
2.6-202210 to 2.6-202303	integer	No	No
2.6-202309 to 2.6-202606	integer, default 1	No	No

Versioned rules that name this field

openrtb.2.6.cattax OpenRTB 2.6 standardized taxonomy selection with cattax across request and bid objects.