IAB Content Taxonomy Reference
Every domain in the URL Categorization Database is classified using both IAB Content Taxonomy v2 and v3, providing granular content categorization with 700+ categories organized across 4 hierarchical tiers. These taxonomies are the advertising industry's standard for content classification, enabling contextual targeting, brand safety, and audience segmentation at scale.
What is the IAB Content Taxonomy?
The IAB (Interactive Advertising Bureau) Content Taxonomy is the advertising industry's standard for content categorization. It provides a hierarchical classification system used by advertisers, publishers, and ad tech platforms to categorize digital content for contextual targeting, brand safety, and audience segmentation.
Both IAB v2 and v3 are included in every database tier at no additional cost.
Tier Structure
The IAB taxonomy uses a 4-tier hierarchy, moving from broad categories to highly specific classifications. Each tier provides an additional level of granularity.
Not all domains have values at every tier level. Tier 1 is always present. Lower tiers are populated only when a more specific classification is available.
IAB Content Taxonomy v2
The widely adopted version of the IAB taxonomy. Contains 700+ categories across 4 tiers and is well-established in the ad tech ecosystem, serving as the foundation for programmatic advertising categorization across major platforms.
IAB Content Taxonomy v3
The latest version of the IAB taxonomy, released to better reflect the modern digital landscape. Includes updated categories for emerging content areas like streaming, podcasts, and creator economy content.
Key differences from v2:
- Updated category names and structure
- Better coverage of modern content types (streaming, podcasts, social commerce)
- Improved granularity in technology and digital media categories
- Aligned with current privacy regulations and contextual targeting needs
v2 vs v3: Which Should I Use?
Both taxonomies are included in every database, so you do not have to choose one exclusively. Here is guidance on when each version is most appropriate.
Use v2 if:
- Your ad tech stack is built on IAB v2
- You need backward compatibility with existing systems
- Your DSP/SSP partners use v2 category IDs
Use v3 if:
- You are building a new system
- You need better coverage of modern content types
- You want the most up-to-date categorization standard
Use both if:
- You serve multiple downstream partners with different requirements
- You want maximum flexibility for category mapping
Both taxonomies are included in every database. You can use v2, v3, or both simultaneously. There is no additional cost for either.
Using IAB Categories for Custom Web Filtering
The 43 web filtering categories included in the database provide broad content classification suitable for most filtering use cases. However, the 700+ IAB categories can be used to extend and refine your web filtering policies with much greater granularity.
For example, if your web filtering policy uses the broad "News" category but you need more specific control, you can map from IAB tier 2 and tier 3 categories to distinguish between "Political News", "Business News", "Technology News", "Entertainment News", and more. This allows you to build highly targeted filtering rules that go far beyond the standard 43 categories.
By combining the web filtering categories with IAB tier data, you can create custom category hierarchies tailored to your organization's specific content policy requirements.