BidRequest.acat

An allow list of advertiser categories in the taxonomy named by BidRequest.cattax. Added in 2.6-202309; send it or BidRequest.bcat, not both.

Currentstring arrayOptionalSince 2.6-202309

Field facts

Path: acat
Object: BidRequest
Type: string array
Requirement: Optional
Added: OpenRTB 2.6-202309
Spec section: 3.2.1

How it is used

Use it when a placement should carry only a few kinds of advertising, for example a children's app that accepts only education and family brands. When cattax is absent, IAB Content Taxonomy 1.0 codes are assumed.

Example

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

{
  "id": "req-1",
  "acat": [
    "IAB2",
    "IAB19"
  ]
}

Common mistakes

Sending acat alongside bcat (openrtb.fields.mutually_exclusive).
Mixing codes from two taxonomies in one list. cattax applies to the whole list.

Version history

Added in OpenRTB 2.6-202309, 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
2.6-202309 to 2.6-202606	string array	No	No

Related fields

Other BidRequest fields

For a walkthrough of the whole object, read Bid request anatomy.