What is the IAB Ad Product Taxonomy, and why do ads get blocked?
Part of Brand suitability
The short answer
The IAB Ad Product Taxonomy is IAB Tech Lab's standard list of the products and services an ad promotes, such as Alcohol, Gambling or Pharmaceuticals. Publishers and SSPs use its IDs to refuse whole categories of ads. They send those IDs in the bid request's bcat field, block named advertiser domains in badv, and filter any bid that matches.
Key takeaways
- The Ad Product Taxonomy labels what an ad sells; it says nothing about the page the ad appears on.
- In OpenRTB, bcat carries blocked categories, cattax says which taxonomy they come from, and badv carries blocked advertiser domains.
- If cattax is missing, OpenRTB assumes Content Taxonomy 1.0, a deprecated list, so a mismatch between partners can block or pass the wrong ads.
- Loss reason codes 205 (advertiser exclusions) and 209 (category exclusions) show that a block, not a low bid, cost the impression.
What does the IAB Ad Product Taxonomy classify?
Definition
- Ad Product Taxonomy
- IAB Tech Lab's standard vocabulary for the product or service advertised in a creative. Publishers and SSPs use it to decide which kinds of ads they accept, and to measure how those ads perform.
IAB Tech Lab's taxonomy repository (opens in a new tab) describes the Ad Product Taxonomy as a "standardized nomenclature for describing the product or service being advertised within a creative unit." It aims to give publishers stronger signals to control which types of ads reach them through automated channels, and to measure those ads against internal goals. The subject is the ad: a whiskey ad is Alcohol on a cocktail blog and on a weather site alike.
The current version is 2.0. The published 2.0 file (opens in a new tab) lists 583 categories, which we counted in October 2026: 45 at tier 1, 333 at tier 2 and 205 at tier 3. Politics (1474), for example, has children for Elections (1476), Political Action Committees (1477), Political Donations (1480) and Ballot measures (1475). Page meaning is a separate job handled by the IAB Content Taxonomy, and the two lists use different IDs.
| Category | ID | Children in the 2.0 file |
|---|---|---|
| Alcohol | 1002 | Bars, plus beer, wine and spirits rows |
| Cannabis | 1049 | Cannabis Consumables, Cannabis Stores, CBD Consumables, CBD Topicals |
| Dating | 1259 | Casual Relationships, Serious Relationships |
| Dieting and Weightloss | 1291 | Food Logging, Weightloss Services, Workout and Step Tracking Applications |
| Gambling | 1361 | Casinos, Contests, Lottery, Sports Betting, Virtual Betting |
| Non-Fiat Currency | 1448 | Cryptocurrency Exchanges, Cryptocurrency Stock |
| Pharmaceuticals | 1473 | None listed |
| Politics | 1474 | Ballot measures, Elections, Political candidates, Political Donations |
| Weapons and Ammunition | 1576 | Firearm and ammunition rows |
How do publishers block advertiser categories?
A publisher sets its blocks once, in its ad server or in each SSP it sells through, and the systems apply them to the auctions that follow. Tech Lab's guidance says the taxonomy "is primarily used by publishers and SSPs when blocking categories of advertisements." It also calls the categories "just a shorthand to help weed out obviously unwanted ads" and points to the advertiser domain, adomain in OpenRTB, as what sellers ultimately use to evaluate an advertiser.
Ad servers can keep their own category lists too. Google Ad Manager's Block sensitive categories (opens in a new tab) page, checked October 21, 2026, lets a publisher exclude categories such as Dating, Get rich quick, Politics, Religion, Social casino games and Weight loss. Google says its "system classifies ads automatically, and we don't rely on advertiser-provided categorization," and does not guarantee it will block every related ad.
What do the bcat and badv fields do in a bid request?
The OpenRTB 2.6 specification (opens in a new tab) carries publisher restrictions in the bid request and asks the bidder to describe its creative in matching fields on the bid.
| Field | Where it sits | Definition in OpenRTB 2.6 |
|---|---|---|
| bcat | Bid request | "Blocked advertiser categories using the specified category taxonomy." |
| acat | Bid request | "Allowed advertiser categories"; only one of acat or bcat should be present |
| cattax | Bid request | "The taxonomy in use for bcat"; default 1 |
| badv | Bid request | "Block list of advertisers by their domains (e.g., 'ford.com')." |
| bseat | Bid request | "Block list of buyer seats (e.g., advertisers, agencies) restricted from bidding" |
| cat | Bid | "IAB Tech Lab content categories of the creative", in the taxonomy named by the bid's cattax |
| adomain | Bid | "Advertiser domain for block list checking" |
The numbers in cattax come from the AdCOM 1.0 list of category taxonomies (opens in a new tab). Value 3 is Ad Product Taxonomy 1.0 and value 8 is Ad Product Taxonomy 2.0. Values 1 and 2 are Content Taxonomy 1.0 and 2.0, which AdCOM marks deprecated and recommends not be used. So a request carrying bcat with cattax 8 tells bidders that the IDs mean Ad Product 2.0 categories.
Why might a publisher block a whole product category?
A category block is a business rule, not a judgment about one advertiser. Tech Lab's guidance names legal requirements such as not showing alcohol to certain age groups, rules on foods high in fat, sugar and salt, and plain preference, such as "a sports website not wanting gambling advertising on their inventory." It also asks publishers to choose which categories go to manual creative review, naming politics, religion, debated sensitive social issues, dating, dieting and weight loss, media and sexual health.
| Reason for the block | Example | What the buyer can do |
|---|---|---|
| Age or legal limits | Alcohol or dating ads on a site with young readers | Accept the block; plan sites whose readers fit the product |
| Rules that vary by place | Cannabis or gambling, which Tech Lab notes differ in legality by region | Check the rule for each state or province before asking for an exception |
| Editorial fit | A sports site refusing gambling, a parenting site refusing weight loss | Ask the publisher which tier 2 or tier 3 rows are blocked; a narrow block may leave room |
| Sensitive categories held for review | Political or religious ads queued for manual approval | Submit creative early so review does not eat the flight |
How can a buyer find out why ads were blocked?
Exchanges report a lost bid through the loss notice URL, lurl, and the AUCTION_LOSS macro, using the loss reason codes listed in OpenRTB 3.0 (opens in a new tab). The spec notes that exchange policy may preclude loss notices, so codes can be missing or replaced by the exchange's own reports.
| Code | Name in the spec | What it points to for the buyer |
|---|---|---|
| 104 | Buyer Seat Blocked | The seat itself is barred, whatever the creative |
| 202 | Creative Filtered, Disapproved by Exchange | The exchange's own creative review rejected the ad |
| 205 | Creative Filtered, Advertiser Exclusions | The adomain matched a badv entry or a seller's advertiser block |
| 209 | Creative Filtered, Category Exclusions | A category on the bid matched bcat or a seller's category block |
| 210 | Creative Filtered, Creative Attribute Exclusions | An attribute such as autoplay audio matched battr |
Five steps to trace a category block
- Pull loss reasons by site. Ask the DSP or SSP for losses split by domain and code, so blocked impressions are not mixed with lost auctions.
- Read the creative's labels. Find the cat values and the taxonomy version the DSP assigned to each creative, since the label may come from the DSP rather than the advertiser.
- Read the seller's blocks. Ask the SSP which bcat IDs and which cattax value the publisher sends, and whether badv lists the advertiser.
- Compare versions. If one side uses Content 1.0 and the other Ad Product 2.0, ask both to check Tech Lab's mapping between the two.
- Fix the label or accept the block. Correct a wrong label through the DSP's review process; when the label is right, move budget to sites that accept the category.
What does a category block investigation look like for a supplement brand?
Fictional example
A protein powder maker in Minnesota
A fictional sports nutrition maker in Minneapolis and Duluth runs display ads for whey protein beside fitness and endurance sports sites in Minnesota and Wisconsin. Two of the strongest sites on its inclusion list deliver almost nothing. The loss report shows code 209 on both, not lost auctions.
The DSP labels the protein ad Vitamins and Supplements (1253) and a meal replacement creative Weightloss Supplements (1255). One publisher blocks Dieting and Weightloss (1291) under Ad Product 2.0. The other sends bcat with no cattax, so its Content 1.0 Weight Loss code is read differently by each partner.
The team does not relabel anything to slip past the rule. It keeps the weight management creative off both sites, asks the second publisher's SSP to send cattax 8, and confirms the protein creative is now accepted. The client gets a note listing which categories each site refuses.
Where does PlacementGraph fit when ads are blocked by category?
What should a buyer check before a campaign in a restricted category?
Ad category readiness checklist
- Each creative's category label and taxonomy version are written down, per DSP.
- Creatives for different products are split, so one sensitive label does not hold back the rest.
- The plan names which sites or sections refuse the brand's category, from the publisher or SSP.
- Creatives in categories held for manual review were submitted with time to spare before launch.
- Loss reasons are reported by code and domain from the first week of the flight.
Blocks on the ad side and suitability on the page side answer opposite questions: the publisher decides which ads its readers see, and the brand decides which pages it funds. For the page side, see how brand safety categories are defined and how pre bid filtering applies them.
Frequently asked questions
Can an advertiser choose its own Ad Product category?
The label can come from the DSP or the exchange's creative review rather than the advertiser. Google Ad Manager, for one, says it classifies ads automatically and does not rely on advertiser provided categories. An advertiser can ask for a wrong label to be corrected, but choosing a label to avoid a publisher's block defeats the publisher's rule.
Does Ad Product Taxonomy 2.0 replace Content Taxonomy 1.0 for ads?
For describing ads, yes. Tech Lab tells advertisers that categorize ads to move to Ad Product Taxonomy 2.0, and it publishes mappings in both directions between Content 1.0 and Ad Product 2.0. Some sellers still send Content 1.0 codes, which is why the cattax value matters.
Is a blocked ad category the same as a brand safety problem with the ad?
No. A category block means the publisher does not accept that kind of product, even when the ad is perfectly ordinary. A creative with offensive or inappropriate content is a separate matter, which the taxonomy marks with the Ad Safety Risk flag alongside the product category.
Are ad category blocks the same for US and Canadian publishers?
No single rule applies. Each publisher sets its own blocks, and Tech Lab warns implementers that categories such as cannabis and gambling differ in legality across regions, and that age limits apply to alcohol and dating ads. A buyer running in both countries should check the blocks site by site.
Sources
- Taxonomies repository README (opens in a new tab)IAB Tech Lab
- Ad Product Taxonomy 2.0 (TSV) (opens in a new tab)IAB Tech Lab
- Taxonomy implementation guidance (opens in a new tab)IAB Tech Lab
- OpenRTB 2.6 specification (opens in a new tab)IAB Tech Lab
- AdCOM 1.0: List of category taxonomies (opens in a new tab)IAB Tech Lab
- OpenRTB 3.0: List of loss reason codes (opens in a new tab)IAB Tech Lab
- Block sensitive categories (opens in a new tab)Google Ad Manager Help
Researched and written by PlacementGraph Research. Read how we research, source and update these pages. Corrections: diana@placementgraph.com.