IAB Audience Taxonomy 1.1

IAB Audience Taxonomy 1.1 is the IAB Tech Lab's standard audience segment vocabulary, released in 2022. It defines ~1,500 segment IDs across four top-level branches: Demographics (age, gender, income, education, etc.), Interests (auto, sports, parenting, technology, etc.), Intent (in-market for X, recent purchase of X), and Behavior (frequent flyer, app user, etc.). Each segment ID is a stable integer that maps to a human-readable name and a path.

On the wire, audience segments ride in the bid request's user.data[].segment[] array, each one tagged with a "segtax" code identifying which taxonomy it belongs to. For IAB AT 1.1, segtax=4. A bid request can carry segments from multiple taxonomies — IAB AT 1.1 for demographic basics plus a vendor-specific taxonomy for higher-fidelity behavioral signals.

Version 2.0 has been in late draft since 2024 and will likely ship with segtax=7 once finalized. Adoption will be gradual — old and new will coexist on the wire for years, the way IAB Content Taxonomy 1.0 and 2.x coexisted from 2018-2022.

Trillboards' DSP API exposes audiences in IAB AT 1.1 for everything taxonomy-mappable and a Trillboards-specific segtax=600 namespace for CV-unique signals like cohort composition. Buyers can mix both in a single targeting clause.