Website Category Lookup
What is this website about, and should we trust it? A category lookup answers that in a second, for one site or for a whole list. Enter a domain and get its topic categories, the country it serves, the audience it attracts and how popular it is.
This page explains single and bulk lookups, what every field in the result means, and when it makes more sense to explore the database or license the whole file.
Single lookup or bulk lookup
The result is the same either way. What changes is how many domains you check, how often, and where the answers need to go. Many teams start with single checks to learn the data, then move to bulk files once they trust it.
Single lookup
One domain, one answer, on screen. Ideal for curiosity, spot checks and settling a question about one site.
- Check a new partner, supplier or publisher
- See why a site was blocked or allowed
- Test how the data labels your own website
- Try a few domains before buying a list
Use the domain checker.
Bulk lookup
A file of domains in, a file of categories out. Ideal for lists you already hold, such as CRM accounts or log extracts.
- Categorize thousands of accounts at once
- Label a month of DNS or proxy logs
- Audit a publisher list for brand safety
- Build training data for your own models
See pricing for volumes.
What the result contains
Here is the shape of a lookup result, shown for an illustrative news site. Every field is explained below it. A bulk result has exactly the same fields, one row per domain.
| Field | What it tells you | Typical use |
|---|---|---|
| Web filtering categories | One or more of 59 categories, ranked by how much of the site they describe | Allow and block rules, brand safety |
| IAB v3 tiers | Topic in the current IAB Content Taxonomy, up to four levels | Contextual targeting, research |
| IAB v2 tiers | The same topic in the older IAB version still used by many ad stacks | Compatibility with existing ad platforms |
| Personas | Audience types the site attracts | Audience planning, segmentation |
| Country | The country the site mainly serves, if clear | Market filters, sales territories |
| Popularity groups | Size band worldwide and within the country | Prioritising, cutting the long tail |
The taxonomies behind these fields are listed on the taxonomy page and the IAB categories list.
How to read a lookup result
Most questions about lookups come from the same few situations. Knowing them makes results much easier to use, and saves you from treating a deliberate answer as an error.
Several categories
A site with three categories covers three subjects. The first describes the largest part of the site. Use it alone for strict rules, or all of them for broad ones.
Shallow IAB tiers
If Tier 3 is empty, the site is general within its Tier 2 topic. That is a deliberate answer, not missing data.
No country
Global sites and sites without a clear market have no country. Do not treat that as "United States" by default.
No popularity group
The site is not among the most visited domains, or its traffic is too small to rank. It is still categorized.
Parked
The domain shows a parking or for-sale page. It has no real content, so it carries no topic beyond that.
Not found
Usually a very new, inactive or rarely visited domain. New domains are added as they appear; see the newly registered domains list.
Preparing domains for a bulk lookup
Good input gives good match rates. A few minutes of preparation often lifts the share of matched rows noticeably.
Strip the URL
Remove "https://", paths, query strings and ports. Categories describe whole sites.
Lowercase
Domains are not case sensitive, but matching is simpler when everything is lowercase.
Drop "www."
Look up example.com rather than www.example.com. Most sites are listed without it.
Fall back to the root
If shop.brand.com has no match, try brand.com. Most subdomains share the parent's subject.
Deduplicate
Look up each domain once, then join the answer back to every row that uses it.
Skip noise
Leave out IP addresses, internal hostnames and technical domains you already know.
| Raw input | Send as |
|---|---|
https://www.Example.com/blog/post?id=7 | example.com |
shop.example.co.uk:443 | shop.example.co.uk, then example.co.uk |
m.example.de | m.example.de, then example.de |
[email protected] | example-firm.com |
Common lookup scenarios
These are the questions people bring to a lookup most often, and how the result answers them.
| Question | Field to read | What a useful answer looks like |
|---|---|---|
| Is this site safe to advertise on? | Web filtering categories | No gambling, adult, weapons or similar risk categories among the labels |
| What industry is this company in? | IAB v3 Tier 2 and Tier 3 | A label under Industries or Business, such as Logistics or Manufacturing |
| Why did our filter block this site? | Web filtering categories | The category that matches a block rule in your policy |
| Is this publisher big enough for our campaign? | Popularity groups | A global or country band that fits your reach target |
| Which market does this site serve? | Country | One country, or empty for global sites |
| Who reads this site? | Personas | Audience types that match your target customer |
Checking a suspicious domain
Security analysts often look up a domain from an alert or a reported email. The category is one input among several, and it works best in a short routine.
1. Look up the category
Malware, phishing or suspicious labels settle the question at once. So does a clear, ordinary business topic in most cases.
2. Check popularity
A well-known, highly ranked site is rarely the attacker's own domain, though it can still host abused content.
3. Consider age
No result, or a parked result, on a domain that looks like a brand name is a strong reason to dig deeper.
4. Compare with context
Does the category fit the email or link that pointed to it? A "bank" link that leads to a shopping site is a red flag.
Using lookup results in your tools
A bulk lookup returns a plain file keyed by domain. That makes it easy to bring the answers into whatever you already use. Keep the lookup date with the result, so you know how fresh each answer is when you reuse it later.
Spreadsheets
Open the CSV result next to your list and use a lookup formula on the domain column to pull in categories.
SQL databases
Load the result into a table and join it to your own data on the domain, with a fallback join on the root domain.
CRM systems
Import the categories as custom account fields, matched on the normalised website field.
Data warehouses
Take the result as Parquet and query it alongside logs or bid data. See domain list download formats.
Who uses website category lookups
Ad operations
Check a publisher before adding it to a campaign, or audit a site list for brand safety. See brand safety advertising.
Security analysts
Look up an unfamiliar domain in an alert to decide quickly whether it deserves attention. See cybersecurity threat intelligence.
Sales and RevOps
Add industry labels to accounts that only have a website, then route and score them.
IT and network admins
Answer "why is this site blocked?" by checking which category it carries.
SEO and content teams
Check how competitors and link partners are categorized. See SEO competitor analysis.
Researchers
Label a sample of domains for a study without building a classifier from scratch.
Lookup or full database?
Lookups are perfect for questions. Once lookups become part of a system that runs all day, a local copy of the data is usually faster, cheaper per answer and more private.
| Situation | Best fit | Why |
|---|---|---|
| A few sites, now and then | Single lookup | No setup at all |
| A list of thousands, once | Bulk lookup | One file in, one file out |
| Repeated bulk jobs every month | Category list or database subset | The whole slice is already in your hands |
| Real-time decisions, such as ad bidding or filtering | Full database held locally | Very fast answers, no network calls |
| Sensitive logs that must not leave your network | Full database held locally | No domain ever leaves your systems |
| Browsing categories to understand the data | Explore the database | See real examples by category |
Match rates: what to expect
The share of your domains that get a category depends mostly on what is in your list. These patterns hold across most lookup jobs. Measure both rates, by unique domain and weighted by traffic or records, because they tell different stories about coverage.
Traffic-weighted is high
Logs are dominated by popular sites. Weighted by visits, nearly every request lands on a categorized domain.
Unique hosts is lower
Counted per unique host, rare and technical names pull the rate down. That is normal and rarely matters.
CRM lists vary
Lists with clean company domains match well. Lists full of typos, old domains or webmail addresses match less.
New domains lag
A domain with no content yet cannot be categorized. It is picked up once a site appears.
Turning lookup results into actions
A category on its own is just a label. These are typical actions teams attach to groups of categories once lookups run at scale.
| Category group | Examples | Network policy | Advertising |
|---|---|---|---|
| Security risks | Malware / Phishing / Suspicious | Block | Exclude |
| Adult and gambling | Adult, Gambling, Dating | Block on most networks | Exclude for most brands |
| Bypass tools | VPN / Proxy / Anonymizers, Remote Access Tools | Block or restrict | Usually exclude |
| Sensitive news | Political, News/Media with conflict topics | Allow | Brand choice |
| Productivity risks | Gaming, Streaming Media, Social Networking | Limit at work or school | Allow, often high reach |
| Everyday topics | Shopping, Travel, Food & Drink, Business | Allow | Target by topic |
| Infrastructure | CDN / Hosting / Infrastructure, URL Shorteners | Allow, watch shorteners | Not relevant |
Honest limits of any lookup
A domain lookup is a strong signal, but it has limits worth knowing before you build decisions on it.
Sites, not pages
The answer describes the whole site. One article on a news site can be about gambling while the site stays News/Media.
Platforms are mixed
Hosting and blogging platforms carry content from many owners. Their category reflects the platform, not each user's page.
Sites change
A domain can change owner and subject. Regular refreshes catch this, but a lookup is always a snapshot of the latest check.
Empty sites stay unknown
Domains with no content get no topic. Plan a rule for unknown domains in any automated policy.
Looking up your own website
Site owners check their own domain more often than you might think. The category decides whether your site is reachable on filtered networks and which ad campaigns can appear on it.
Publishers
A clear, safe category helps your pages qualify for contextual campaigns and brand-safe inclusion lists.
Online shops
A Shopping category keeps your shop reachable on office and school networks that block unknown or risky sites.
New businesses
A brand-new domain may show no category at first. Publishing real content about what you do is the fastest way to get one.
Privacy and lookups
Lookups only need domains. Keeping it that way protects your users and your own data. It also makes files smaller and jobs faster, because one domain can stand for thousands of log lines or URLs.
Send domains, not URLs
Full URLs can contain search terms, session tokens or personal details. Strip them before any lookup.
No user identifiers
Do not attach user names, IP addresses or device IDs to a lookup file. The category does not depend on who visited.
Keep logs at home
For DNS or proxy logs, a local copy of the data means no domain list ever leaves your network. See privacy compliance.
Website category lookup: questions
What is a website category lookup?
It is a check that takes a domain and returns what the site is about: web filtering categories, IAB v2 and v3 topics, and context such as country, audience personas and popularity group.
Can I look up many websites at once?
Yes. Bulk lookups take a file of domains and return a file with categories for each one. For very large or constant volumes, a licensed copy of the database queried locally is usually the better fit.
What does the lookup result contain?
The domain, its web filtering categories, IAB v2 and v3 categories up to Tier 4, audience personas, country where clear, and global and country popularity groups.
Why does a site have more than one category?
Many sites cover several subjects. Categories are ranked by how much of the site they describe, so you can use the first one or all of them.
What happens if a domain is not found?
The result says the domain is not in the database. That usually means a very new, inactive or rarely visited domain. New domains are categorized as they appear.
Should I send full URLs or domains?
Domains are enough. Categories describe whole sites, so paths and query strings add nothing and are best removed before a lookup.
Is a lookup the same as a category list?
No. A lookup starts from domains you already have and tells you their categories. A category list starts from a category and gives you all the domains in it. See websites by category.
How fast is a bulk lookup?
That depends on the size of the file. For very large or recurring jobs, a local copy of the data removes waiting time altogether, because the lookup runs on your own systems.
Can I look up subdomains?
Yes. Where a subdomain works as its own site, it can have its own categories. Otherwise fall back to the root domain, which usually shares the same subject.
Do lookups include personal data?
No. The result describes websites only. It contains no names, emails or other details about the people who own or visit a site.
I think a category is wrong. What now?
Sites change, and the data is reviewed and validated regularly. Check again after the next refresh, and look at whether the site itself recently changed subject.
Look up one site, or all of them
Check a single domain in the domain checker, or tell us about your volumes for bulk lookups and full database access.
Bulk lookups and pricing Explore the database