Where does the data come from?

Companize is based on the public KVK Handelsregister. We collect, structure and refresh that data ourselves, so you can use it through one fast, consistent API.

What is a KVK number?

A KVK number (KVK-nummer) is the unique 8-digit identifier the Dutch Chamber of Commerce assigns to every business registered in the Handelsregister. It identifies the legal entity as a whole. With Companize you can look up any Dutch company by its KVK number in a single API call.

What's the difference between a KVK number, an establishment number and an RSIN?

The KVK number (8 digits) identifies the registered business. An establishment number (vestigingsnummer, 12 digits) identifies one specific location of that business. The RSIN is the legal-entity identifier used by the Dutch Tax Authority. Every Companize profile returns all three where available.

SBI codes (Standaard Bedrijfsindeling) classify what a company actually does, its economic activity. Each profile returns the company's SBI activity codes, so you can filter, segment or enrich businesses by industry.

How do I look up a Dutch company by KVK number?

Call the lookup endpoint with the 8-digit KVK number and you get the full company profile back as JSON in one request: legal form, status, trade names, SBI activity codes, addresses and establishments. Don't know the number? Search by name first to find it.

Can I search by company name as well as KVK number?

Yes. You can run a full-text search by name and get ranked results, or look up an exact company by its KVK or establishment number.

Is KVK Handelsregister data public and free to use?

Company information in the Handelsregister is public by law, so you can look a company up without that company's permission. Reuse does come with conditions, and some data may be subject to KVK rights or the GDPR. With Companize you pay for the convenience of a fast, structured API; lawful use within your own application remains your responsibility.

How fresh is the data?

We refresh the data on a fixed cycle. New registrations and changes are included, so you don't serve stale data and don't have to scrape or maintain your own pipeline.

Can I use this for KYC, onboarding or enriching a list of companies?

Yes. Companize is a convenient data source for customer onboarding, verifying company details and keeping your CRM clean. Look companies up one by one or enrich a list by name or KVK number and get a consistent structured profile back every time. For formal KYC or AML (Wwft) processes you'll typically combine it with additional sources.

How is this different from the official KVK API?

Companize gives you one clean REST endpoint, JSON everywhere, full-text search, typo tolerance and predictable latency, without you managing scrapers or stitching fields together from separate sources. You work with the same public register data, but with a developer-friendly experience and enrichment on top.

Is this allowed under GDPR?

Most register data describes legal entities, which falls outside GDPR. Some records (such as sole proprietorships) can include personal data, and there you remain the controller for how you use it in your own application. We only serve what the register publishes openly; lawful use within your product is your responsibility.

We're finalising pricing for launch, with a free tier to start building and usage-based plans as you grow. Join the waitlist and we'll share details beforehand.

We're onboarding early users from the waitlist now. Add your email and you'll be among the first to get access and an API key.

Free tier on real, live data. Join the waitlist.

Every Dutch company, one API call away.

Let your users find the right company data as they type: name, address and KVK number fill in automatically.

Companize makes Dutch company data available through a fast, modern API with complete, current profiles as JSON, in under 100 ms.

Join the waitlist Explore the API

Company & address autofill in forms

Responses in under 100 ms

Always current, clean data

GET /v1/companies/ 69599084 43 ms 200 OK

{
  "kvk_number": "69599084",
  "name": "Coolblue B.V.",
  "legal_form": "Besloten vennootschap",
  "status": "active",
  "trade_names": ["Coolblue"],
  "sbi_activities": [
    { "code": "4791", "description": "Retail via internet" }
  ],
  "establishment": {
    "establishment_number": "000019625863",
    "founded_on": "1999-05-31",
    "employees": 2500
  },
  "visiting_address": {
    "street": "Weena 664",
    "postal_code": "3012 CN",
    "city": "Rotterdam"
  }
}

Three APIs, one platform

Pick the API that fits your use case

Companize is three APIs you can use on their own or combine; same key, same subscription.

Company Data API

Search by name or KVK number and get complete company profiles: legal form, status, trade names, activities, addresses and establishments. Everything from the register in one structured response.

Learn more

Address Validation API

Validate and complete Dutch addresses as your users type, or resolve a postcode and house number to the exact street, city and municipality. Only real addresses reach your systems.

Learn more

VAT Validation API

Validate a Dutch or EU VAT (BTW) number and resolve it to the company behind it. Confirm a customer's tax details at signup or checkout on verified numbers.

Learn more

Why developers choose us

The fastest way to work with Dutch company data

Companize does the hard part: collecting, structuring and keeping company data current. You ship features instead of maintaining scrapers.

Search by name or KVK number: Full-text search across millions of Dutch companies, or an exact match on KVK or establishment number. Typo-tolerant and ranked by relevance. Your user types the first few letters, picks the right company, and name, address and KVK number fill in automatically.
Enriched profiles: Go beyond the register: enrich profiles with website, social profiles, employee count and key financials. Exactly what you need for CRM enrichment and onboarding.
Clean, correct data: Because we refresh the data on a fixed cycle, the company and address details your customers fill in and store stay correct. Fewer typos and duplicate records, fewer corrections later and a cleaner database, with no scraping or maintenance on your side.
Built for speed: A purpose-built index returns results in milliseconds, with predictable latency. Autocomplete feels instant and your real-time onboarding and checkout flows stay snappy.
Developer-first: A clean REST API with JSON everywhere, API keys you manage yourself, sensible pagination and clear docs. Integrate in minutes.
Onboarding & verification: Structured company data based on the public Handelsregister: a reliable source to verify businesses, onboard customers and keep your CRM clean.

Try it yourself

Type (part of) a company name and get live results straight from the API

Same response as GET /v1/autocomplete

Complete coverage

All the business data you need

Every company profile comes fully structured and ready to use; no parsing HTML, no piecing fields together from different sources.

The registration data comes from the Handelsregister. On top of that we enrich every profile with extra company data, in one consistent schema, whether it's a one-person business or a multinational with hundreds of establishments.

Registration data

Company & trade names
KVK number
Establishment number
RSIN identifier
Legal form
Registration status
SBI activity codes
Founding date
Visiting address
Postal address
Establishments

Enrichment

Website
Email addresses
Phone numbers
Social profiles
Company logo
Employee count
Key financials (revenue, total assets)
Officers & owners
Registry publications
VAT validation

Developer experience

A REST API you'll enjoy using

Authenticate with a bearer token, call a single endpoint, get JSON. That's it.

Autocomplete companies

Low-latency suggestions while your users type — name, city and KVK number in a single call.

GET /v1/autocomplete?q=coolb

curl https://api.companize.nl/v1/autocomplete \
  -G --data-urlencode "q=coolb" \
  -H "Authorization: Bearer $API_KEY"

Look up a company

Fetch a complete profile by KVK number. Add include=enrichment to get contact details, VAT number and financials in the same request.

GET /v1/companies/69599084?include=enrichment

curl "https://api.companize.nl/v1/companies/69599084?include=enrichment" \
  -H "Authorization: Bearer $API_KEY"

Explore the full API reference

Coverage you can build a business on

The whole Dutch register, kept current and served fast.

Companies indexed: 4M+
Fields per company: 40+
Median response time: <100ms
Uptime target: 99.9%

Pricing

Plans that scale with your usage

Start free, upgrade when you need more. Every plan includes the full API. Higher tiers raise your monthly quotas and limits.

Starter

For small apps and side projects.

€15 /mo

Join the waitlist

5,000 autocompletes
2,500 profile fetches
200 enrichments
Address & VAT validation included
5 requests per second
max 15 results per page
pagination up to 1,000 results
Email support

Growth

Pro

High volume, exports and priority support.

€135 /mo

Join the waitlist

120,000 autocompletes
100,000 profile fetches
6,000 enrichments
Address & VAT validation included
40 requests per second
max 50 results per page
pagination up to 10,000 results
Priority + DPA support
Data export

Free

€0/mo

Build your prototype on real, live production data.

1,000 autocompletes · 250 profile fetches · 50 enrichments · 2 requests per second

Join the waitlist

Usage quotas reset monthly. Need higher volumes, bulk export or an SLA? Get in touch.

Frequently asked questions

: Companize is based on the public KVK Handelsregister. We collect, structure and refresh that data ourselves, so you can use it through one fast, consistent API.
: A KVK number (KVK-nummer) is the unique 8-digit identifier the Dutch Chamber of Commerce assigns to every business registered in the Handelsregister. It identifies the legal entity as a whole. With Companize you can look up any Dutch company by its KVK number in a single API call.
: The KVK number (8 digits) identifies the registered business. An establishment number (vestigingsnummer, 12 digits) identifies one specific location of that business. The RSIN is the legal-entity identifier used by the Dutch Tax Authority. Every Companize profile returns all three where available.
: SBI codes (Standaard Bedrijfsindeling) classify what a company actually does, its economic activity. Each profile returns the company's SBI activity codes, so you can filter, segment or enrich businesses by industry.
: Call the lookup endpoint with the 8-digit KVK number and you get the full company profile back as JSON in one request: legal form, status, trade names, SBI activity codes, addresses and establishments. Don't know the number? Search by name first to find it.
: Yes. You can run a full-text search by name and get ranked results, or look up an exact company by its KVK or establishment number.
: Company information in the Handelsregister is public by law, so you can look a company up without that company's permission. Reuse does come with conditions, and some data may be subject to KVK rights or the GDPR. With Companize you pay for the convenience of a fast, structured API; lawful use within your own application remains your responsibility.
: We refresh the data on a fixed cycle. New registrations and changes are included, so you don't serve stale data and don't have to scrape or maintain your own pipeline.
: Yes. Companize is a convenient data source for customer onboarding, verifying company details and keeping your CRM clean. Look companies up one by one or enrich a list by name or KVK number and get a consistent structured profile back every time. For formal KYC or AML (Wwft) processes you'll typically combine it with additional sources.
: Companize gives you one clean REST endpoint, JSON everywhere, full-text search, typo tolerance and predictable latency, without you managing scrapers or stitching fields together from separate sources. You work with the same public register data, but with a developer-friendly experience and enrichment on top.
: Most register data describes legal entities, which falls outside GDPR. Some records (such as sole proprietorships) can include personal data, and there you remain the controller for how you use it in your own application. We only serve what the register publishes openly; lawful use within your product is your responsibility.
: We're finalising pricing for launch, with a free tier to start building and usage-based plans as you grow. Join the waitlist and we'll share details beforehand.
: We're onboarding early users from the waitlist now. Add your email and you'll be among the first to get access and an API key.

Be first to build on Companize

Join the waitlist for early access, a free tier at launch and updates as we roll out. No spam, just the important stuff.

We'll only use your email to contact you about early access. Unsubscribe anytime.