Google Ad Manager again fills cat and pagecat in bid requests

Starting October 15, 2026, Google Ad Manager again populates site.cat, site.pagecat, app.cat and app.pagecat in Authorized Buyers, Open Bidding and SDK bid requests outside the EEA, UK and Switzerland. Buyers must match the cattax selector to the IAB Content Taxonomy version (1.0, 2.2, 3.0, 3.1) or deal filters and brand-safety blocks will target the wrong vertical.

• OpenRTB 2.6 defaults cattax to 1 (Taxonomy 1.0) when the field is omitted
• Taxonomies 2.2, 3.0 and 3.1 map to cattax 6, 7 and 9 respectively
• Taxonomy 3.1 has 704 categories, including new genre codes such as Thriller
• OpenRTB 2.6-202501 added gtax and genres fields for CTV genre signaling