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Industry Standard

IAB Content Taxonomy v3

703 categories across 4 hierarchical tiers. The taxonomy that powers programmatic advertising at every major exchange, SSP, and DSP on the planet. Classify any URL or domain in real time. Our API also returns IAB v2 categories in every call for backward compatibility.

703Categories
4Tier Levels
6Taxonomies Supported
102MDomains Pre-classified
Programmatic Advertising
Brand Safety
Content Targeting
Audience Segmentation
Supply-Side Platforms
Demand-Side Platforms
Overview

What Is the IAB Content Taxonomy v3?

The IAB Tech Lab Content Taxonomy version 3 is the definitive classification system for digital content. Maintained by the Interactive Advertising Bureau, it is the standard that programmatic advertising platforms, brand-safety vendors, and publisher networks rely on to categorize web content consistently across the open internet.

Version 3 replaced the older v2 taxonomy with a cleaner, deeper hierarchy. Where v2 had flat or two-level groupings that left large swaths of the modern web inadequately classified, v3 introduces a structured four-tier tree with 703 granular categories. The result is sharper audience segmentation, more precise contextual targeting, and fewer brand-safety false positives.

Every URL you submit to our API is classified against the full v3 tree. You receive all matching categories with confidence scores, from Tier 1 verticals down to Tier 4 micro-segments, in a single API call that completes in under 50 milliseconds.

Technology & Computing
Artificial Intelligence
Machine Learning
Natural Language Processing
Each URL can match multiple branches simultaneously. A page about AI-powered fintech would return categories from both Technology & Computing and Business & Finance.
Hierarchy

Four Tiers of Increasing Granularity

The IAB v3 taxonomy is organized as a four-level tree. Each tier adds precision, from broad industry verticals down to ultra-specific content segments that power surgical ad targeting.

1

Tier 1 — Verticals

28 top-level industry categories that cover every corner of the web. Automotive, Business & Finance, Technology & Computing, Sports, Health, News, Travel, and more. Broad enough for high-level reporting, precise enough to route entire inventory pools.

2

Tier 2 — Subcategories

Approximately 160 subcategories that break each vertical into industry-specific segments. Under Technology & Computing, for instance, you get Artificial Intelligence, Consumer Electronics, Cybersecurity, Programming Languages, and a dozen more.

3

Tier 3 — Detailed Topics

Around 340 fine-grained content classifications. This is where targeting gets surgical: not just Artificial Intelligence, but Machine Learning, Computer Vision, Robotics, and Natural Language Processing as distinct targetable segments.

4

Tier 4 — Micro-segments

175 ultra-specific targeting segments at the leaf level of the taxonomy. Built for campaigns that need hyper-precise contextual alignment: not just Running, but Marathon Training, Trail Running, or Running Shoe Reviews.

703Total Categories
28Top-level Verticals
6Taxonomy Standards Returned
102MDomains in Offline Database
Pipeline

How IAB v3 Classification Works

From URL submission to categorized JSON response, the entire pipeline completes in under 50 milliseconds. Here is what happens inside every API call.

URL Submitted

You send a URL or bare domain to our REST endpoint. The system validates the input, resolves redirects, and queues the request for content retrieval. Bulk endpoints accept up to 100 URLs per call.

Content Retrieved

Our distributed crawler fetches the page from globally distributed edge nodes. We extract the full text body, meta tags, Open Graph data, structured schema markup, and headline hierarchy.

NLP Analysis

A multi-model NLP pipeline processes the extracted content. Transformer-based language models analyze semantic meaning, entity relationships, topical signals, and contextual cues across 100+ languages.

Multi-label Classification

The analyzed content is matched against all 703 IAB v3 categories simultaneously. Multi-label classification means a single page can match multiple categories across different branches of the taxonomy tree.

Confidence Scoring

Each matched category receives a confidence score from 0 to 1. Scores reflect how strongly the content aligns with that category. You can filter by threshold to control precision versus recall for your use case.

JSON Response

The full classification result is returned as structured JSON. Every matched category includes the complete hierarchical path, the confidence score, and the tier level. Typical response time: 30 to 45 milliseconds.

Tier 1

All 28 Top-Level Verticals

Every piece of content on the web maps to at least one of these 28 verticals. From there, the taxonomy drills down through three more tiers to reach 703 leaf categories.

Automotive
Books & Literature
Business & Finance
Careers
Education
Events & Attractions
Family & Parenting
Fine Art
Food & Drink
Healthy Living
Hobbies & Interests
Home & Garden
Medical Health
Movies
Music & Audio
News & Politics
Personal Finance
Pets
Pop Culture
Real Estate
Religion & Spirituality
Science
Shopping
Sports
Style & Fashion
Technology & Computing
Television
Travel
Video Gaming
Integration

One API Call, Full IAB v3 Classification

Integrating IAB v3 classification into your stack takes minutes, not weeks. Our REST API accepts any URL or domain and returns the complete classification hierarchy as structured JSON. No training data required, no model management, no infrastructure to maintain.

Works with every language and framework. Drop in a single HTTP call from Python, Node.js, PHP, Go, Ruby, Java, or plain cURL. The response includes every matched category with its full hierarchical path and confidence score.

  • Single REST endpoint, standard JSON responses
  • Bulk classification: up to 100 URLs per request
  • Multi-language support: 100+ languages classified natively
  • Cached results for repeat lookups, zero-latency on hot domains
import http.client conn = http.client.HTTPSConnection( "www.websitecategorizationapi.com") payload = 'query=techcrunch.com' \ '&api_key=your_api_key' \ '&data_type=url' headers = { 'Content-Type': 'application/x-www-form-urlencoded' } conn.request("POST", "/api/iab/iab_web_content_filtering.php", payload, headers) res = conn.getresponse() data = res.read() print(data.decode("utf-8"))
Applications

Built for Every Side of the Ad Ecosystem

IAB v3 classification drives decisions across the entire programmatic supply chain, from publisher inventory tagging to real-time bid-request enrichment.

Programmatic Ad Targeting

Enrich bid requests with IAB v3 categories so DSPs can make contextually relevant targeting decisions in milliseconds. Buyers get higher match rates, publishers see higher CPMs, and users see ads that align with the content they are reading.

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Brand Safety Enforcement

Build real-time brand-safety filters that block ad placements on pages classified under sensitive categories. Protect advertiser reputation by ensuring creative never appears alongside content that violates brand guidelines or industry regulations.

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Content Recommendation Engines

Power next-article and related-content widgets by matching IAB v3 categories across your content library. Users stay engaged longer when recommendations are taxonomically aligned rather than driven by simple keyword overlap.

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Publisher Inventory Classification

Automatically tag every page in your publisher inventory with standardized IAB v3 categories. Sell contextual targeting segments directly to buyers without manual content tagging. Keep inventory categorization current as content changes daily.

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Audience Analytics

Understand what your audience actually reads by mapping browsing behavior to IAB v3 categories. Build interest-based audience segments from observed content consumption, not self-reported demographics or probabilistic modeling.

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Regulatory Compliance

Enforce COPPA, GDPR, and regional advertising regulations by classifying content before ad delivery. Automatically prevent child-directed ads from appearing on age-inappropriate content, and maintain auditable classification records for compliance reviews.

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Get Started

Classify Any URL with IAB v3 in Milliseconds

Full access to all 703 categories across all four tiers, with confidence scores and multi-label classification included in every plan.

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