Question 1

What is the IAB Content Taxonomy Mapper?

Accepted Answer

The IAB Content Taxonomy Mapper is an open-source tool that converts content categorization from the older IAB 2.x standard to the newer IAB 3.0 format. It generates OpenRTB and VAST-ready category IDs that can be used directly in programmatic advertising workflows.

Question 2

Why migrate from IAB 2.x to 3.0?

Accepted Answer

IAB 3.0 provides better separation between topic categorization and contextual vectors, improved brand safety signals, and more granular content classification. The industry is moving to 3.0 for better interoperability and more precise targeting capabilities.

Question 3

Does it require an internet connection?

Accepted Answer

No, the mapper is designed for local-first processing. All taxonomy data is bundled with the package, so you can run it in air-gapped environments without external API calls. Optional features like embeddings and LLM re-ranking can use local models via Ollama.

Question 4

How accurate is the mapping?

Accepted Answer

The mapper uses a multi-stage matching pipeline: deterministic exact matching, fuzzy string matching with configurable thresholds, and optional semantic enrichment using embeddings. You can also add manual overrides for edge cases. Each mapping comes with a confidence score, so low-confidence rows can go to review.

Question 5

Which cattax value should the mapper output use?

Accepted Answer

9, for IAB Content Taxonomy 3.1, which is what the mapper's catalog contains. In AdCOM's List: Category Taxonomies, 7 is Content Taxonomy 3.0 and 2 is Content Taxonomy 2.0, so a cattax of 2 tells a receiver to read 3.x IDs as 2.0 codes. Every 3.0 ID is also a 3.1 ID, so if a buyer only accepts 3.0, send the same IDs with cattax 7. Mapper versions up to 1.0.0, the current release on npm and PyPI, default to 2, so set cattax explicitly until 1.1.0 ships.

Question 6

Is there a JavaScript/TypeScript version?

Accepted Answer

Yes, the tool is available as both a Python package (iab-mapper on PyPI) and a TypeScript/JavaScript package (@mixpeek/iab-mapper on npm). Both versions provide the same functionality with zero external dependencies for the core mapping logic.

IAB Content Taxonomy Mapper

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