DEV Community: Matías Maquieira

Get a Company's EU VAT Number from Its Company Number: the Rules for 10 Countries (with Code)

Matías Maquieira — Tue, 06 Oct 2026 22:37:55 +0000

Get a Company's EU VAT Number from Its Company Number: the Rules for 10 Countries (with Code)

Your onboarding form asks for a company number, your invoicing system needs a VAT number, and the customer typed only one of them. In many European countries the VAT number is not a separate secret: it is the company's own identifier in a fixed format. In others there is no rule at all. Here are the rules, a function you can paste, and the one thing a derived number cannot tell you.

The rules

Country	Built from	VAT number	Example
Spain	NIF (company letters A–W)	`ES` + NIF	`ESA46103834`
France	SIREN (9 digits)	`FR` + 2-digit key + SIREN	`FR27552032534`
Poland	NIP (10 digits)	`PL` + NIP	`PL7740001454`
Norway	organisasjonsnummer (9 digits)	`NO` + number + `MVA`	`NO923609016MVA`
Finland	Y-tunnus `1234567-8`	`FI` + the 8 digits	`FI01120389`
Sweden	organisationsnummer (10 digits)	`SE` + number + `01`	`SE556810898801`
Belgium	enterprise number (10 digits)	`BE` + number	`BE0202239951`
Croatia	OIB (11 digits)	`HR` + OIB	`HR18928523252`
Denmark	CVR (8 digits)	`DK` + CVR	`DK24256790`
Switzerland	UID `CHE-123.456.789`	UID + `MWST` (TVA/IVA)	`CHE103867266MWST`

No rule exists for the UK (a VAT number is its own registration with HMRC), Ireland, Slovakia (the IČ DPH is not derived from the IČO) or Estonia (the KMKR is not the registry code). There you need the number from the company or from a register that publishes it.

France: the key

The only rule with arithmetic. The two-digit key is (12 + 3 × (SIREN mod 97)) mod 97:

def fr_vat(siren: str) -> str:
    key = (12 + 3 * (int(siren) % 97)) % 97
    return f"FR{key:02d}{siren}"

assert fr_vat("552032534") == "FR27552032534"   # Danone

All ten as one function

import re

def vat_from_company_number(country: str, number: str) -> str | None:
    """The VAT number a company's identifier implies, or None where no rule exists."""
    s = re.sub(r"[\s.\-/]", "", number or "").upper()
    d = re.sub(r"\D", "", s)
    if country == "ES":
        return f"ES{s}" if re.fullmatch(r"[ABCDEFGHJNPQRSUVW]\d{7}[0-9A-J]", s) else None
    if country == "FR" and len(d) == 9:
        return f"FR{(12 + 3 * (int(d) % 97)) % 97:02d}{d}"
    rules = {"PL": (10, "PL", ""), "NO": (9, "NO", "MVA"), "FI": (8, "FI", ""), "SE": (10, "SE", "01"),
             "BE": (10, "BE", ""), "HR": (11, "HR", ""), "DK": (8, "DK", ""), "CH": (9, "CHE", "MWST")}
    if country in rules and len(d) == rules[country][0]:
        n, prefix, suffix = rules[country]
        return f"{prefix}{d}{suffix}"
    return None

Note the Spanish check: a NIF that starts with X, Y or Z is a foreigner's personal NIE, never a company VAT number.

The one thing a derived number cannot tell you

The format is right; whether the company is actually registered for VAT is a separate fact. Plenty of small companies, holding companies and non-profits are not. Before you put a derived number on an invoice or zero-rate a cross-border sale, check it against VIES, the European Commission's validation service:

curl "https://api.prometiam.com/functions/v1/risk-api/vat/FR27552032534" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

Two registers answer the registration question themselves. Norway's register flags whether a company is in the VAT register, and Finland's register says so for many companies. In both, a company the register marks as not VAT-registered has no VAT number at all, so building one would be wrong.

Or let the API do it

Every company object the Prometiam Risk API returns now carries vat_number and vat_number_source: register when the register publishes the number (Estonia) or confirms the company is VAT-registered (Norway, Finland, Belgium), rule when it was built with the rules above, and null where the register says the company is not VAT-registered or no rule exists (UK, Ireland, Slovakia). Search, lookup and VIES checks run on the free 14-day trial (1,000 requests; sign up). For a one-off check without code there is a free VAT number checker.

Slovak Company Data via API: RPO Lookups by IČO or Name, as JSON (2026)

Matías Maquieira — Tue, 06 Oct 2026 22:23:49 +0000

Slovak Company Data via API: RPO Lookups by IČO or Name, as JSON (2026)

Slovakia's Register of Legal Entities (Register právnických osôb, RPO) is open data, published as monthly full files plus daily changes. That is fine for a data team and awkward for a product team that needs one company, now, as JSON. This guide shows how to look up a Slovak company by name or by its IČO in one REST call, what comes back, and what the data does not cover.

What is the RPO?

The RPO, run by the Statistical Office of the Slovak Republic, collects the legal entities registered in Slovakia's source registers, the commercial register (Obchodný register) among them. Each entity has an 8-digit IČO (identification number). The register an entity was filed in, its file number and the court travel with it.

Query it in one call

You need a key. The free plan is a 14-day trial with 1,000 requests, and a key takes about a minute at prometiam.com/signup. Then search by name or by IČO:

curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=SK&name=slovak%20telekom" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=SK&company_number=35763469" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

Then the detail by the id the search returned:

curl "https://api.prometiam.com/functions/v1/risk-api/companies/13000035763469?country=SK" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

What you get back

Slovak Telekom, a.s. as the API returned it on 7 October 2026 (trimmed to the main keys):

{
  "id": 13000035763469,
  "country": "SK",
  "company_number": "35763469",
  "company_name": "SLOVAK TELEKOM, A.S.",
  "identifiers": [{ "type": "ico", "value": "35763469" }],
  "vat_number": null,
  "legal_form": "a.s.",
  "legal_form_family": "public_limited_company",
  "local_legal_form": "121",
  "status": "active",
  "founding_date": "1999-04-01",
  "activity_code": "6110",
  "activity_code_scheme": "SK-NACE-2025",
  "activity_description": "Činnosti drôtových, bezdrôtových a satelitných telekomunikácií",
  "activity_description_en": "Wired, wireless, and satellite telecommunication activities",
  "nace_class": "61.10",
  "address": "BAJKALSKÁ 28",
  "postal_code": "817 62",
  "city": "BRATISLAVA",
  "region": "BRATISLAVSKÝ KRAJ",
  "capital_amount": 864113000,
  "capital_currency": "EUR",
  "register": "Register of Legal Entities (RPO)",
  "registry_details": {
    "source_register": "Obchodný register",
    "registration_number": "Sa/2081/B",
    "registration_court": "Mestský súd Bratislava III"
  }
}

Worth knowing:

Legal form, two ways. legal_form is the abbreviation (a.s., s.r.o., k.s.), local_legal_form is the RPO's own code (121), and legal_form_family is comparable across countries.
Status is standardised. A company in bankruptcy (konkurz) has status: "in_liquidation_insolvent"; restructuring and liquidation have their own values, and local_status keeps the register's word.
No VAT number. The Slovak VAT number (IČ DPH) is a separate registration that no rule derives from the IČO, so vat_number is null and a vat= search is refused for Slovakia.

Limits, stated plainly

Company records only: no officers, and no registry-compliance signal.
Commercial legal persons only: no associations, foundations or other non-commercial entities. Sole traders and other natural persons are never served.
Status includes bankruptcy and restructuring, but there are no insolvency notices for Slovakia.
Monitoring and register-change events (name, status, legal form, registered address) cover Slovakia, dated when the change first appears in the register data.
Contains data from the Register of Legal Entities (RPO), Ministry of Interior and Statistical Office of the Slovak Republic, CC BY 4.0.

One integration, thirteen registers

The same call shape covers Spain, France, the UK, Ireland, Poland, Norway, Finland, Sweden, Belgium, Croatia, Denmark and Estonia. Field list in the API docs; to check one company without code, there is a free IČO lookup.

Estonian Company Data via API: e-Business Register Lookups by Registry Code, KMKR or Name (2026)

Matías Maquieira — Tue, 06 Oct 2026 22:23:48 +0000

Estonian Company Data via API: e-Business Register Lookups by Registry Code, KMKR or Name (2026)

Estonia publishes its company register as open data, which is great, and as a set of bulk files and a separate XML service, which is less great when all you want is "give me this company as JSON". This guide shows how to look up an Estonian company by name, by its 8-digit registry code (registrikood) or by its VAT number (KMKR) in one REST call, what comes back, and the limits of the data.

What is the Estonian e-Business Register?

The e-Business Register (e-äriregister, run by the Centre of Registers and Information Systems, RIK) is where every Estonian company is registered. Each one gets an 8-digit registry code. A VAT-registered company also has a KMKR number, written EE plus 9 digits, which is not the registry code.

Query it in one call

You need a key. The free plan is a 14-day trial with 1,000 requests, and a key takes about a minute at prometiam.com/signup. Then search by name:

curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=EE&name=swedbank" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

By registry code, or by VAT number:

curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=EE&company_number=10060701" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=EE&vat=EE100354546" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

Each hit carries an id. The detail call returns the full company object:

curl "https://api.prometiam.com/functions/v1/risk-api/companies/12000010060701?country=EE" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

What you get back

This is Swedbank AS as the API returned it on 7 October 2026 (trimmed to the main keys):

{
  "id": 12000010060701,
  "country": "EE",
  "company_number": "10060701",
  "company_name": "SWEDBANK AS",
  "identifiers": [
    { "type": "registry_code", "value": "10060701" },
    { "type": "vat", "value": "EE100354546" }
  ],
  "vat_number": "EE100354546",
  "vat_number_source": "register",
  "legal_form": "AS",
  "legal_form_family": "public_limited_company",
  "status": "active",
  "founding_date": "1996-07-11",
  "activity_code": "64191",
  "activity_code_scheme": "EMTAK-2025",
  "activity_description": "Krediidiasutused",
  "activity_description_en": "Other monetary intermediation",
  "nace_class": "64.19",
  "address": "LIIVALAIA TN 34",
  "postal_code": "15040",
  "city": "TALLINN",
  "region": "HARJU MAAKOND",
  "capital_amount": 85000000,
  "capital_currency": "EUR",
  "employees": 1392,
  "register": "Estonian e-Business Register (RIK)"
}

A few things worth knowing:

Two activity-code vintages. Estonian companies report EMTAK codes, and the register holds both EMTAK 2008 and EMTAK 2025 codes depending on when the company last reported. activity_code_scheme tells you which one you got, and nace_class maps either to the NACE class, so you can compare across countries.
The KMKR comes from the register. vat_number_source: "register" means the register published it. There is no rule that turns a registry code into a KMKR, so a company without one has vat_number: null.
Status is standardised. status uses the same values in every country (active, in_liquidation, in_liquidation_insolvent, ...), and local_status keeps the register's own value.

Python in ten lines

import os, requests

BASE = "https://api.prometiam.com/functions/v1/risk-api"
HEAD = {"Authorization": f"Bearer {os.environ['PROMETIAM_API_KEY']}"}

hits = requests.get(f"{BASE}/companies/search", headers=HEAD,
                    params={"country": "EE", "company_number": "10060701"}).json()["data"]
company = requests.get(f"{BASE}/companies/{hits[0]['id']}", headers=HEAD,
                       params={"country": "EE"}).json()["data"]
print(company["company_name"], company["status"], company["vat_number"])

Limits, stated plainly

Company records only: no officers or shareholders, and no registry-compliance signal.
Status includes liquidation and bankruptcy, but there are no insolvency notices for Estonia.
Sole traders (FIE) are never served.
Monitoring (status changes, dissolution, sanctions matches) and register-change events (name, status, legal form, registered address) cover Estonia, dated when the change first appears in the register data.
Contains data from the Estonian e-Business Register (RIK), CC BY 4.0.

Same call, other countries

The same country= pattern works for Spain, France, the UK, Ireland, Poland, Norway, Finland, Sweden, Belgium, Croatia, Denmark and Slovakia, with the same response shape, so a Baltic or Nordic onboarding flow does not need a separate integration per register. The full field list is in the API docs, and there is a free registry code lookup if you just need to check one company.

How to Detect Spanish Company Insolvency and Corporate Events from BORME via API

Matías Maquieira — Tue, 29 Sep 2026 06:59:45 +0000

You can pull a Spanish company's registry profile, its officers, its corporate-event history and its insolvency proceedings from official sources with a few REST calls. No PDF parsing, no scraping, no Spanish-language gazette wrangling. This article shows the exact requests, the JSON as returned today, and how to turn it into a daily KYB risk watchlist.

By Matías Maquieira, Founder of Prometiam.

What is BORME, and where do insolvencies live?

BORME (Boletín Oficial del Registro Mercantil) is Spain's official company-registry gazette. Every registrable corporate act, incorporation, director appointments and removals, share-capital changes, dissolutions and liquidations, is published there on working days. Insolvency proceedings themselves (the concurso de acreedores) are court matters published through the Registro Público Concursal, with their milestones: the filing, the appointment of the insolvency administrator, liquidation, conclusion.

A serious watchlist reads both. The Prometiam API serves BORME acts as corporate events and the concursal notices as an insolvency index, keyed on the same NIF.

Look up a company in one call

You need a key: the free plan is a 14-day trial with 1,000 calls and no card, and a key takes about a minute at prometiam.com/signup.

curl -s "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=ES&name=glovoapp" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

The first match, as returned on 25 September 2026:

{
  "data": [
    {
      "id": 3189007,
      "match_score": 67,
      "company_name": "GLOVOAPP25 SL",
      "company_number": "B24997728",
      "legal_form": "SL",
      "province": "MADRID",
      "address": "C/ ORENSE 4 (MADRID)",
      "postal_code": "28020",
      "status": "active",
      "capital_euros": 3000,
      "founding_date": "2025-12-05",
      "country": "ES"
    }
  ],
  "pagination": { "count": 1, "has_more": true, "next_cursor": null }
}

Then request the full profile by id. It carries the registry coordinates, the current officers under appointments, and the latest acts under recent_events:

curl -s "https://api.prometiam.com/functions/v1/risk-api/companies/3189007?country=ES&include=insolvency,risk_flags" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

{
  "data": {
    "id": 3189007,
    "nif": "B24997728",
    "company_name": "GLOVOAPP25 SL",
    "legal_form": "SL",
    "status": "active",
    "capital_euros": 3000,
    "founding_date": "2025-12-05",
    "registro_seccion": "8",
    "registro_hoja": "M 871839",
    "appointments": [
      { "role_type": "ADM_UNICO", "action": "appointed", "event_date": "2025-12-23",
        "person": { "id": 1920708, "full_name": "<the sole director's name>", "is_legal_entity": false } }
    ],
    "recent_events": [
      { "event_type": "status_change", "event_date": "2025-12-23", "new_value": "DECLARACION_UNIPERSONALIDAD" }
    ],
    "insolvency_proceedings": [],
    "risk_flags": []
  }
}

include=insolvency,risk_flags attaches the concursal notices and any published risk flag (today, the tax authority's large-debtor list) to the same record. Both are empty here, which is what you want to see on a new counterparty. You can also search by NIF directly with ?nif=B24997728 instead of ?name=.

Read the corporate events

Every BORME act about a company is an event with a type, a date, and the link to the gazette PDF it came from. The event stream is on the Starter plan and up (€9.99); the free trial covers the company profile with its officers and the concursal index:

curl -s "https://api.prometiam.com/functions/v1/risk-api/company-events/search?country=ES&company_number=B24997728" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

{
  "data": [
    {
      "id": 17978361,
      "company_id": 3189007,
      "company_name": "GLOVOAPP25 SL",
      "company_number": "B24997728",
      "event_type": "status_change",
      "signal_category": "neutral",
      "event_date": "2025-12-23",
      "new_value": "NOMBRAMIENTOS",
      "event_detail": "GLOVOAPP25 SL. Constitución. Comienzo de operaciones: 5.12.25. [...] Capital: 3.000,00 Euros. Declaración de unipersonalidad. Socio único: GLOVOAPP 23 SA. Nombramientos. Adm. Unico: <the sole director's name>.",
      "notice_url": "https://www.boe.es/borme/dias/2025/12/23/pdfs/BORME-A-2025-244-28.pdf"
    }
  ]
}

Filter with event_type= (director_change, capital_change, dissolution, liquidation, insolvency, name_change, address_change, merger) and a date range. notice_url points at the official PDF, so every event is verifiable at the source.

Catch insolvency proceedings

The concursal index is GET /search. Here is a company in proceedings right now, queried by NIF:

curl -s "https://api.prometiam.com/functions/v1/risk-api/search?vat=B90335910" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

{
  "data": [
    {
      "company_name": "RESEARCH TO SOLVE SOCIEDAD LIMITADA",
      "company_number": "B90335910",
      "status": "insolvency-proceedings",
      "status_detail": "Cese de Administrador concursal",
      "event_type": "insolvency",
      "filing_date": "2026-09-09",
      "source": "Registro Publico Concursal (Spain)"
    },
    {
      "company_name": "RESEARCH TO SOLVE SOCIEDAD LIMITADA",
      "company_number": "B90335910",
      "status": "insolvency-proceedings",
      "status_detail": "Cese de las limitaciones de las facultades de administración",
      "event_type": "insolvency",
      "filing_date": "2024-09-09",
      "source": "Registro Publico Concursal (Spain)"
    }
  ]
}

Each row is one milestone of the proceeding, newest first, with the court's own wording in status_detail. The company's BORME events tell the same story from the registry side: on 2024-09-20 its status changed to CONCURSO_ACREEDORES, then LIQUIDACION, then CIERRE_PROVISIONAL, all on /company-events/search.

The daily watchlist

Run a check each morning over your customers and suppliers, and alert on any new concursal milestone or dissolution:

import os, requests
BASE = "https://api.prometiam.com/functions/v1/risk-api"
HEAD = {"Authorization": f"Bearer {os.environ['PROMETIAM_API_KEY']}"}
WATCHLIST = ["B24997728", "B90335910"]   # counterparty NIFs

for nif in WATCHLIST:
    notices = requests.get(f"{BASE}/search", params={"vat": nif}, headers=HEAD).json()["data"]
    events = requests.get(f"{BASE}/company-events/search",
                          params={"country": "ES", "company_number": nif, "event_type": "dissolution"},
                          headers=HEAD).json()["data"]
    for n in notices:
        print(f"CONCURSAL {nif}: {n['status_detail']} ({n['filing_date']})")
    for e in events:
        print(f"DISSOLUTION {nif}: {e['event_date']} {e['notice_url']}")

If you would rather not poll, POST /monitor with the company's id subscribes it and sends a signed webhook when a corporate event, a status change or a sanctions match is published. A complete version on Cloudflare Workers with Slack alerts is in the BORME watchlist guide.

Scope, stated plainly

Corporate insolvency only. Personal insolvencies are excluded and never returned.
Spain's concursal data is on /search. The separate /insolvency/search index covers nine other markets (FR, DE, GB, AT, CH, NO, FI, US, NL).
Monitoring is available for Spain, Ireland and Poland.
The API reflects what the gazettes and the register publish, on the day they publish it. It is a signal to act on, not a court record.

FAQ

What is a NIF and how do I search by it?
The NIF is Spain's tax identifier for companies: a letter for the legal form, seven digits and a control character. Search with ?nif= on /companies/search or ?vat= on /search. Both are exact lookups.

Does it include directors and capital changes?
Yes. The company record returns current officers under appointments, and the event stream carries appointments, removals and capital increases or reductions, each linked to its BORME act.

How much does it cost?
A free 14-day trial with 1,000 calls and no card. Paid plans are Starter at €9.99 (10,000 calls), Professional at €29.99 (100,000, adds full sanctions screening), Scale at €99.99 (1,000,000) and Enterprise. Data is EU-resident. Sanctions and US export-control screening run on the same key.

Wrapping up

Spanish company data and the insolvency signals most providers miss are a few REST calls away. Start with the free trial, or read the background on what BORME is and how it works.

Look up Irish companies (CRO) in one API call

Matías Maquieira — Sun, 27 Sep 2026 06:59:58 +0000

Looking up an Irish company programmatically usually means scraping the CRO website or buying a heavyweight KYB platform. There is a simpler path: the Prometiam API serves the Companies Registration Office register as JSON over one REST endpoint, sourced from the CRO Open Data Portal. This post shows a runnable curl, the exact response as returned today, a Node snippet, and an honest account of what the data does and does not include.

By Matías Maquieira, Founder of Prometiam.

What is the CRO?

The Companies Registration Office (CRO) is the statutory body that registers companies and business names in Ireland. Every Irish limited company, DAC, PLC and registered branch has a CRO number, a status (active, dissolved, struck off, in liquidation, in examinership), and a registered office address. The CRO publishes a bulk snapshot on the CRO Open Data Portal, licensed CC BY 4.0, which is the source behind the calls below.

Query it in one call

The endpoint is GET /companies/search?country=IE. Authentication is a Bearer key; the free plan is a 14-day trial with 1,000 calls and no card, and a key takes about a minute at prometiam.com/signup.

curl -s "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=IE&name=ryanair" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

The first of nine matches, as returned on 25 September 2026, happens to show why status matters:

{
  "data": [
    {
      "id": 246488,
      "match_score": 67,
      "company_number": "246488",
      "company_name": "RYANAIR.COM LIMITED",
      "legal_form": "LTD - Private Company Limited by Shares",
      "province": "DUBLIN",
      "address": "IRISH LIQUIDATIONS, 7 FITZWILLIAM STREET LOWER, DUBLIN 2",
      "postal_code": "D02 DT85",
      "status": "dissolved",
      "founding_date": "1996-03-21",
      "dissolution_date": "2026-08-22",
      "country": "IE"
    }
  ],
  "pagination": { "count": 9, "has_more": false, "next_cursor": null }
}

A company that was dissolved a month ago, with the liquidator's address as its registered office. A name match is not a verification; the status and dissolution_date fields are.

If you already hold the CRO number, look it up exactly:

curl -s "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=IE&company_number=104547" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

which returns RYANAIR DESIGNATED ACTIVITY COMPANY, legal form DAC, active, incorporated 1984-11-28. Fetch the full record with GET /companies/{id}?country=IE; it adds status_date, the last annual return date (last_ar_date) and next_accounts_due. The same pattern from Node, with the built-in fetch:

const BASE = "https://api.prometiam.com/functions/v1/risk-api";
const KEY = process.env.PROMETIAM_API_KEY;

async function searchIE(name) {
  const url = `${BASE}/companies/search?country=IE&name=${encodeURIComponent(name)}`;
  const res = await fetch(url, { headers: { Authorization: `Bearer ${KEY}` } });
  if (!res.ok) throw new Error(`HTTP ${res.status}`);
  const { data } = await res.json();
  return data;
}

const matches = await searchIE("ryanair");
console.log(matches.map((c) => `${c.company_number} — ${c.company_name} (${c.status})`));

What you get back

Each Irish record is company-level: legal name, CRO number, legal form, status and status date, registered address and Eircode, incorporation and dissolution dates, last annual return and next accounts due. That is enough to verify a company exists, confirm it is still active, and resolve its registered address.

One honest limitation: directors, officers and beneficial ownership are not included. Public access to Ireland's Register of Beneficial Ownership is legally restricted across the EU since the Court of Justice ruling of November 2022, and the CRO open data does not carry officers. You get reliable existence, status and address data; if your use case needs the directors of an Irish company, you need a different, gated source. Better to know that before you integrate than after.

Monitoring

Ireland is one of the three countries with monitoring. POST /monitor with the company's id subscribes it, and a signed webhook reaches you when the status changes, which is exactly the dissolution above, without a daily poll.

UK + Ireland on one key

The same key and the same endpoints serve the UK (Companies House) via ?country=GB:

curl -s "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=GB&name=ryanair" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

This matters after Brexit. Many UK groups hold a Dublin-incorporated subsidiary to keep an EU footprint, so verifying a counterparty often spans both registries. With one schema and one key you flip country=GB to country=IE and back. Where Ireland is company-level only, the UK record carries current and past officer appointments, and persons with significant control are available on the UK side.

FAQ

Is CRO data free or licensed?
The underlying data comes from the CRO Open Data Portal under CC BY 4.0, open data with an attribution requirement. If you republish it, include "Contains Irish Public Sector Data licensed under CC BY 4.0". The API is a paid service with a free 14-day trial; it adds normalisation, search, the UK registry, monitoring and EU-hosted infrastructure.

Does it include directors or UBO?
No. Irish coverage is company-level: name, legal form, status, address, Eircode, dates. UK officers and persons with significant control are available via ?country=GB.

How is this different from the official CRO search?
The official site is built for one-off human lookups, not programmatic access. This API returns normalised JSON, supports name search and exact-number lookup, applies the same schema across six countries (Ireland, the UK, Spain, France, Poland, Norway), and is hosted in the EU.

For the cross-border verification pattern in full, see the guide at prometiam.com/guides/uk-ireland-british-isles-kyb. To try it on a free 14-day trial key, sign up.

Contains Irish Public Sector Data licensed under CC BY 4.0.

How to Query the Polish KRS Company Register via API (2026 Guide)

Matías Maquieira — Fri, 25 Sep 2026 14:52:44 +0000

How to Query the Polish KRS Company Register via API (2026 Guide)

You can query Poland's KRS company register with one REST call: send a company name, a 10-digit KRS number, a NIP or a REGON and get back the legal entity's name, NIP (tax ID), REGON, legal form, PKD activity code, registered address, share capital and registration date as JSON. No court-portal scraping, no captcha. Below is a runnable request, the exact response shape as returned today, and an honest rundown of what is and is not in the data.

By Matías Maquieira, Founder of Prometiam.

What is the KRS?

The KRS (Krajowy Rejestr Sądowy, National Court Register) is Poland's official register of legal entities: limited companies (sp. z o.o.), joint-stock companies (S.A.), partnerships, foundations and associations. It is maintained by the Ministry of Justice and is the authoritative answer to "does this Polish company legally exist, and what are its statutory details". Sole traders are not in the KRS; they live in a separate register, CEIDG.

Query it in one call

You need a key. The free plan is a 14-day trial with 1,000 calls and no card, and a key takes about a minute at prometiam.com/signup. Then search by name:

curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=PL&name=ORLEN" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

Or look a company up directly by its KRS number (10 digits, zero-padded):

curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=PL&company_number=0000028860" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

This is the response, as returned on 9 September 2026:

{
  "data": [
    {
      "id": 28860,
      "company_number": "0000028860",
      "nip": "7740001454",
      "regon": "61018820100000",
      "company_name": "ORLEN SPÓŁKA AKCYJNA",
      "legal_form": "SPÓŁKA AKCYJNA",
      "province": "MAZOWIECKIE",
      "city": "PŁOCK",
      "address": "CHEMIKÓW 7, 09-411 PŁOCK",
      "postal_code": "09-411",
      "status": "active",
      "capital_amount": 1451177561.25,
      "capital_currency": "PLN",
      "founding_date": "2001-07-19",
      "country": "PL"
    }
  ],
  "pagination": { "count": 1, "has_more": false, "next_cursor": null },
  "meta": {
    "attribution": "Source: Krajowy Rejestr Sądowy (KRS), Ministry of Justice, Poland.",
    "coverage_note": "Poland is company-level (KRS active legal entities). Directors, insolvency (KRZ) and beneficial ownership (CRBR) are not yet included; sole traders (CEIDG) are separate."
  }
}

Note that the meta block states the scope on every call. The same thing in Python, standard library only:

import os, urllib.parse, urllib.request, json

BASE = "https://api.prometiam.com/functions/v1/risk-api"
HEAD = {"Authorization": f"Bearer {os.environ['PROMETIAM_API_KEY']}"}

def search_krs(name):
    qs = urllib.parse.urlencode({"country": "PL", "name": name})
    req = urllib.request.Request(f"{BASE}/companies/search?{qs}", headers=HEAD)
    with urllib.request.urlopen(req) as r:
        return json.load(r)["data"]

for c in search_krs("ORLEN"):
    print(c["company_number"], c["nip"], c["company_name"], c["status"])

To pull the full record for one entity, follow up with the detail endpoint using the numeric id:

curl "https://api.prometiam.com/functions/v1/risk-api/companies/28860?country=PL" \
  -H "Authorization: Bearer $PROMETIAM_API_KEY"

The detail adds voivodeship, the PKD code in activity_code (19.20.Z for ORLEN), the registered address split into parts, and the dates the record was first and last seen in the register.

What you get back

For every KRS entity the API returns the company-level fields:

Name, the full registered legal name
KRS number (company_number), the 10-digit court register id
NIP, the tax identification number most KYB checks key on
REGON, the national statistics number
Legal form, for example spółka akcyjna or spółka z ograniczoną odpowiedzialnością
PKD code, Poland's activity classification (the NACE equivalent), on the detail record
Registered address, city, postal code and voivodeship
Share capital in PLN
Registration date and status

The honest caveat, and the API says it on every response: this is company-level data only. Board members, KRZ insolvency proceedings and CRBR beneficial ownership are not exposed yet. If your KYB flow needs the management board or a UBO chain, you still need a supplementary source for that field. Better to know that before you integrate than to discover a null in production.

Monitoring Polish counterparties

Poland is one of the three countries with monitoring. POST /monitor with the company's id subscribes it, and you receive a signed webhook when its status changes, so a dissolution or a name change reaches you without a daily poll.

Why this matters now

The EU's Anti-Money Laundering Regulation applies from 10 July 2027 and harmonises customer due diligence across the Union, including verification of legal entities against official registers. Teams onboarding Polish counterparties today are building the checks they will be audited on then. A programmatic way to confirm that a counterparty exists, is active and matches the NIP on the invoice is the first of those checks, and the one most often still done by hand against the court portal.

How this compares to the alternatives

Scraping the KRS portal. The official portal is built for one-off human lookups. Scraping it means brittle HTML parsing, session handling and rate-limit roulette, and it breaks whenever the markup changes. A typed JSON API removes that maintenance surface.

Free per-entity lookup tools. Fine for a one-off check. They fall down when you need to verify hundreds of counterparties on a schedule, want a stable JSON contract, or need EU data residency for an audit trail. If you only ever check one company a week, a free lookup is the right call; an API earns its keep at volume.

FAQ

Is KRS data free to reuse?
The register is public official data, so the facts themselves are not proprietary. What you pay an API for is delivery: normalised JSON, search, uptime and EU-hosted infrastructure, not a licence on the raw facts.

How do I look up a company by NIP?
Pass it directly: GET /companies/search?country=PL&nip=7740001454 is an exact match, and regon= works the same way (9 or 14 digits). Every response carries the KRS number, the NIP and the REGON, so you can store all three. There is also a free KRS, NIP and REGON lookup on the site that runs the same call without a key.

Does it include directors or beneficial owners?
Not yet. Poland is company-level: name, KRS, NIP, REGON, legal form, PKD, address, capital, dates, status. Board members, KRZ insolvency and CRBR data are planned, not live, so do not build a UBO check on this endpoint today.

How much does it cost?
A free 14-day trial with 1,000 calls and no card. Paid plans are Starter at €9.99 for 10,000 calls, Professional at €29.99 for 100,000 (adds full sanctions screening), Scale at €99.99 for 1,000,000, and Enterprise. Data is EU-resident.

The same country= pattern works across the other registries on the API, Spain, France, the UK, Ireland and Norway, so one integration covers six jurisdictions with one response shape. The deeper walkthrough is the Poland KYB API guide; a free trial key is at prometiam.com/signup.