Overview

ARES (Administrativni registr ekonomickych subjektu -- Administrative Register of Economic Subjects) is the central information system of the Czech Republic that aggregates data from multiple public registers into a unified query interface. Operated by the Czech Ministry of Finance (Ministerstvo financi CR), ARES serves as the authoritative meta-registry for all economic subjects registered in the Czech Republic, encompassing approximately 3 million active entities including commercial companies, sole proprietors, non-profit organizations, and government bodies.

The system was launched in 2004 and underwent a major modernization in 2022, transitioning from legacy XML-based SOAP services to a modern REST API with JSON responses. The new ARES API (ares.gov.cz/ekonomicke-subjekty-v-be/rest) provides structured access to company identification data, statutory bodies, registered addresses, business activities, and cross-references to source registries. This modernization significantly improved data quality, response times, and integration capabilities.

For OSINT analysts and compliance professionals, ARES is the essential starting point for any investigation involving Czech entities. It provides the canonical ICO (Identifikacni cislo osoby -- company identification number) and DIC (Danove identifikacni cislo -- tax identification number) that serve as primary keys across all Czech public registries. A single ARES query returns aggregated information from the Commercial Register (obchodni rejstrik), Trade Licensing Register (zivnostensky rejstrik), Statistical Register (RES), VAT payer registry (DPH), and other source systems, eliminating the need to query each registry independently for basic entity verification.

ARES data is updated in near-real-time as source registries propagate changes, though synchronization delays of up to 24 hours can occur for certain data types. The system processes millions of queries daily from government agencies, financial institutions, legal firms, and compliance departments conducting KYC (Know Your Customer) and AML (Anti-Money Laundering) verification.

Data Sources and Coverage

ARES aggregates data from the following Czech public registries and information systems, each contributing specific data categories to the unified entity profile.

Source Registry	Czech Name	Data Contributed
Commercial Register	Obchodni rejstrik	Company name, legal form, registered capital, statutory bodies, seat address
Trade Licensing Register	Zivnostensky rejstrik (RZP)	Trade licenses, business activities, responsible representatives
Statistical Register	Registr ekonomickych subjektu (RES)	CZ-NACE codes, employee count ranges, turnover categories
VAT Payer Registry	Registr platcu DPH	VAT registration status, DIC number, unreliable payer flag
Excise Duty Registry	Registr platcu spotrebni dane	Excise duty payer registrations
RVPO	Registr verejnych vyzkumnych instituci	Public research institutions
RCNS	Registr celne-neprimych subjektu	Customs subjects
Register of Foundations	Evidence nadaci a nadacnich fondu	Foundations and endowment funds
Register of Institutes	Evidence ustavu	Registered institutes

Coverage Statistics

Metric	Value
Total Registered Entities	~3,000,000
Active Commercial Companies	~600,000
Active Sole Proprietors	~1,800,000
Non-Profit Organizations	~150,000
Government Bodies	~20,000
Daily Query Volume	~5,000,000
Data Freshness	Near-real-time (up to 24h delay for some sources)

API Integration

New REST API (2022+)

The modernized ARES API provides RESTful endpoints with JSON responses, replacing the legacy XML/SOAP services.

Base URL: https://ares.gov.cz/ekonomicke-subjekty-v-be/rest

Endpoint	Method	Description
`/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/vyhledat`	POST	Full-text search for economic subjects
`/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/{ico}`	GET	Lookup by ICO (company ID)
`/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/overeni-dic/{dic}`	GET	DIC (tax ID) verification
`/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/{ico}/statisticke-udaje`	GET	Statistical data for entity
`/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/{ico}/vazby`	GET	Cross-registry references

Rate Limits

Access Type	Limit	Authentication
Public API	Recommended 1 req/sec	None required
Burst Tolerance	~5 req/sec	None required
Bulk Downloads	Available via open data portal	Registration

curl Examples

# Lookup company by ICO
curl -s "https://ares.gov.cz/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/00000001" \
  -H "Accept: application/json"

# Search by company name
curl -s -X POST "https://ares.gov.cz/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/vyhledat" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -d '{"obchodniJmeno": "Prismatic", "start": 0, "pocet": 10}'

# Validate DIC (tax identification number)
curl -s "https://ares.gov.cz/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/overeni-dic/CZ12345678" \
  -H "Accept: application/json"

# Get statistical data
curl -s "https://ares.gov.cz/ekonomicke-subjekty-v-be/rest/ekonomicke-subjekty/00000001/statisticke-udaje" \
  -H "Accept: application/json"

Query Examples

# Search by company name
{:ok, results} = Ares.search(name: "Prismatic")
# => %{total: 3, entities: [%{ico: "12345678", nazev: "Prismatic s.r.o.", ...}, ...]}

# Lookup by ICO (company identification number)
{:ok, company} = Ares.get_by_ico("12345678")
# => %Ares.Entity{
#   ico: "12345678",
#   dic: "CZ12345678",
#   nazev: "Prismatic s.r.o.",
#   pravni_forma: %{kod: "112", nazev: "Spolecnost s rucenim omezenym"},
#   datum_vzniku: ~D[2020-01-15],
#   adresa: %{ulice: "Vaclavske namesti", cislo: "1", obec: "Praha", psc: "11000"},
#   ...
# }

# Validate DIC (tax identification number)
{:ok, valid?} = Ares.validate_dic("CZ12345678")
# => true

# Get full details including statutory bodies
{:ok, details} = Ares.get_full_details("12345678")
# => %{entity: %{...}, statutory_bodies: [...], business_activities: [...]}

# Batch lookup for compliance screening
{:ok, batch_results} = Ares.batch_lookup(["12345678", "87654321", "11111111"])

# Search by address
{:ok, results} = Ares.search(address: %{obec: "Praha", ulice: "Vaclavske namesti"})

# Search with NACE code filter
{:ok, results} = Ares.search(name: "software", nace: "62.01")

Data Schema

Entity Response Structure

%Ares.Entity{
  ico: "12345678",
  dic: "CZ12345678",
  nazev: "Example s.r.o.",
  pravni_forma: %{
    kod: "112",
    nazev: "Spolecnost s rucenim omezenym"
  },
  datum_vzniku: ~D[2020-01-15],
  datum_zaniku: nil,
  adresa: %{
    ulice: "Vaclavske namesti",
    cislo_domovni: "846",
    cislo_orientacni: "1",
    obec: "Praha",
    cast_obce: "Nove Mesto",
    mestska_cast: "Praha 1",
    psc: "11000",
    stat: "CZ"
  },
  predmety_podnikani: [
    %{kod: "62.01", nazev: "Programovani pocitacu"},
    %{kod: "62.02", nazev: "Poradenstvi v oblasti IT"}
  ],
  statutarni_organ: %{
    nazev: "Jednatel",
    clenove: [
      %{jmeno: "Jan", prijmeni: "Novak", funkce: "jednatel",
        datum_vzniku_funkce: ~D[2020-01-15]}
    ]
  },
  zakladni_kapital: %{
    vyse: 200_000,
    mena: "CZK",
    splaceno: 200_000
  },
  velikostni_kategorie: "10-19 zamestnancu",
  zdroj: ["or", "rzp", "res", "dph"]
}

Key Data Fields

Field	Czech Name	Type	Description
`ico`	ICO	String(8)	Unique company identification number
`dic`	DIC	String(12)	Tax identification number (CZ + ICO)
`nazev`	Nazev	String	Official legal name
`pravni_forma`	Pravni forma	Code	Legal form (s.r.o., a.s., etc.)
`datum_vzniku`	Datum vzniku	Date	Date of incorporation
`datum_zaniku`	Datum zaniku	Date	Date of dissolution (nil if active)
`adresa`	Sidlo	Struct	Registered seat address
`predmety_podnikani`	Predmety podnikani	List	Business activities (CZ-NACE codes)
`statutarni_organ`	Statutarni organ	Struct	Directors, board members
`zakladni_kapital`	Zakladni kapital	Struct	Registered capital

Use Cases

KYC/AML Compliance Verification

Financial institutions and obligated entities under Czech AML law (Act No. 253/2008 Sb.) use ARES as the primary source for customer identification and verification. ARES queries confirm entity existence, verify ICO/DIC numbers, identify statutory representatives, and establish the legal form and business activities of counterparties. Automated ARES integration enables real-time KYC checks during customer onboarding.

Corporate Due Diligence

Before entering business relationships, organizations query ARES to verify company details, assess business activity scope, and identify management personnel. The cross-registry aggregation provides a comprehensive initial screening that would otherwise require separate queries to five or more registries.

Investigative Entity Profiling

OSINT analysts use ARES as the foundation for Czech entity investigations, establishing canonical identifiers (ICO, DIC) that enable efficient pivoting across other registries such as Justice.cz, CUZK, Registr smluv, and Hlidac statu. The statutory body data reveals personal connections that can be mapped into relationship graphs.

Tax Compliance Monitoring

Automated DIC validation through ARES ensures that business partners maintain valid VAT registrations. Combined with the DPH unreliable payer registry, this prevents joint liability exposure from transactions with non-compliant counterparties.

Statistical and Market Analysis

Researchers and market analysts use ARES's CZ-NACE classifications and size categories to segment the Czech business landscape, analyze industry composition, and track new company formation trends.

Limitations

Data Synchronization Delays: While ARES aims for near-real-time updates, some source registries propagate changes with delays of up to 24 hours. For time-critical verification (e.g., same-day incorporation), direct queries to source registries may be necessary.

Historical Data: ARES provides current state only; it does not maintain full historical records. For historical company data (former names, previous addresses, past directors), the Commercial Register at Justice.cz provides the complete audit trail.

No Beneficial Ownership: ARES does not include beneficial ownership (skutecny vlastnik) data. This information is available through the Evidence skutecnych vlastniku accessible via Justice.cz.

Sole Proprietor Limitations: Data for sole proprietors (OSVC) is less comprehensive than for commercial companies, often limited to name, ICO, and registered address without detailed business activity descriptions.

No Financial Statements: ARES does not include financial statements or annual reports. These are filed with the Commercial Register (Sbirka listin) at Justice.cz.

Legal and Ethical Considerations

ARES data is public information under Czech law (Act No. 111/2009 Sb., on basic registers). All information available through ARES is considered public and its use does not require consent from data subjects. However, users should be aware of several legal considerations.

The processing of personal data obtained from ARES (names, addresses of statutory representatives) must comply with GDPR requirements. While the data is publicly available, its aggregation, profiling, or use for purposes incompatible with the original collection purpose may trigger GDPR obligations, including the requirement to establish a lawful basis for processing under Article 6.

Automated bulk collection from ARES should respect the recommended rate limits and terms of service. The Czech Ministry of Finance provides bulk data exports through the open data portal (data.gov.cz) for analytical use cases that would otherwise require excessive API queries.

Commercial redistribution of ARES data is generally permitted under Czech open data legislation, provided appropriate attribution is maintained and the data is not misrepresented as coming from an unauthorized source.

Integration with Prismatic Platform

Prismatic Platform integrates ARES as the foundational Czech entity identification and verification source. The integration architecture ensures that ARES serves as the canonical starting point for all Czech entity investigations and compliance checks.

Entity Resolution Pipeline

defmodule Prismatic.Czech.EntityResolver do
  @moduledoc """
  Resolves Czech entities starting from ARES, then enriching
  from specialized registries based on entity type and
  investigation requirements.
  """

  def resolve(ico) when is_binary(ico) do
    with {:ok, ares_entity} <- Ares.get_by_ico(ico),
         {:ok, enriched} <- enrich_from_registries(ares_entity) do
      {:ok, %ResolvedEntity{
        canonical: ares_entity,
        justice: enriched[:justice],
        dph: enriched[:dph],
        rzp: enriched[:rzp],
        hlidac: enriched[:hlidac],
        cuzk: enriched[:cuzk],
        confidence: calculate_confidence(enriched)
      }}
    end
  end
end

Cross-Registry Correlation

ARES ICO numbers serve as the primary join key across all Czech registries in the platform. When a new entity enters the system -- whether from a contract search, property lookup, or compliance screening -- the ARES adapter establishes the canonical entity profile that subsequent enrichment modules build upon. The platform caches ARES responses with a 24-hour TTL, respecting the recommended query rate while ensuring data freshness.

Automated Compliance Screening

The platform's compliance pipeline automatically queries ARES as part of multi-source KYC checks. ARES entity data is cross-referenced with EU and OFAC sanctions lists, the DPH unreliable payer registry, insolvency proceedings, and Hlidac statu risk ratings to produce composite risk assessments.

Best Practices

Cache Aggressively: ARES data changes infrequently for most entities. Implement a 24-hour cache for ICO lookups and a 1-hour cache for search results to minimize API load and improve response times.

Use ICO as Primary Key: Always use ICO for definitive entity lookups. Name-based searches may return multiple results due to common business names and require disambiguation.

Validate ICO Format: Czech ICO numbers are 8-digit strings with a check digit (modulo 11 algorithm). Validate format before querying to avoid unnecessary API calls.

Handle Dissolved Entities: Check datum_zaniku (dissolution date) to confirm entity status. Dissolved entities remain in ARES but are no longer economically active.

Cross-Reference Source Registries: For critical decisions, verify ARES data against the source registry (e.g., Justice.cz for statutory bodies, RZP for trade licenses). ARES aggregation introduces potential synchronization gaps.

Monitor API Changes: The ARES API underwent a major version change in 2022. Subscribe to the Ministry of Finance technical announcements for advance notice of schema changes or service migrations.

Justice.cz - Commercial Register with detailed filings and beneficial ownership
RZP - Trade Licensing Register with activity details
Insolvencni rejstrik - Czech insolvency proceedings
VR.cz - Czech Business Registry with beneficial owners
DPH - VAT payer registry for tax compliance verification
Hlidac statu - Government watchdog with risk analytics
CUZK - Cadastral office for property ownership
EU Sanctions - EU sanctions list for entity screening

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ARES

Capabilities

Try ARES

Overview

Data Sources and Coverage

Coverage Statistics

API Integration

New REST API (2022+)

Rate Limits

curl Examples

Query Examples

Data Schema

Entity Response Structure

Key Data Fields

Use Cases

KYC/AML Compliance Verification

Corporate Due Diligence

Investigative Entity Profiling

Tax Compliance Monitoring

Statistical and Market Analysis

Limitations

Legal and Ethical Considerations

Integration with Prismatic Platform

Entity Resolution Pipeline

Cross-Registry Correlation

Automated Compliance Screening

Best Practices

Connect & Contribute

Intelligence Network

Related Content

Agent Ecosystem

Applications

Doctrine

ARES

Capabilities

Try ARES

Overview

Data Sources and Coverage

Coverage Statistics

API Integration

New REST API (2022+)

Rate Limits

curl Examples

Query Examples

Data Schema

Entity Response Structure

Key Data Fields

Use Cases

KYC/AML Compliance Verification

Corporate Due Diligence

Investigative Entity Profiling

Tax Compliance Monitoring

Statistical and Market Analysis

Limitations

Legal and Ethical Considerations

Integration with Prismatic Platform

Entity Resolution Pipeline

Cross-Registry Correlation

Automated Compliance Screening

Best Practices

Related Providers

Connect & Contribute

Intelligence Network

Related Content

Agent Ecosystem

Applications

Doctrine