Yes. ARES REST API v3 is free, needs no key and no registration. It covers registry basics: name, IČO, address, legal form and CZ-NACE codes. It does not include financial figures, employee counts or any contact data, and heavy use can trigger IP blocking.
Czech register data, enriched and stable
ARES API - Czech Business Register Data
ARES is a solid free lookup for Czech registry basics. When you need more than the raw register, CompanyData delivers 3.4M+ Czech business records with CZ-NACE codes, financials, contacts and powerful filters through one REST API with predictable limits.
3.4M+ Czech businesses
Official CZ-NACE codes on every record
No IP bans, predictable rate limits
What Is the ARES API?
ARES (Administrativní registr ekonomických subjektů) is the Czech Ministry of Finance's register of economic subjects, aggregating around ten source registers including the obchodní rejstřík.
The official ARES REST API v3 is free and needs no key: you can fetch any subject by its 8-digit IČO and get the legal name, address, legal form and CZ-NACE codes. It is a genuinely good public service, with limits: undocumented throttling with opaque IP bans, register-specific deeply nested payloads, financial statements only as PDFs in the Sbírka listin, and no contact or employee data at all. The 2023 v2 to v3 cutover also broke the legacy XML API with little notice.
CompanyData complements the register with what ARES leaves out: revenue, employee counts, email, phone, website, plus search filters ARES does not offer. One flat JSON shape, one API for Czechia and 200+ other countries.
Compare Data Points
ARES returns core registry facts. CompanyData delivers 50+ enriched data points per Czech business in a single call.
| Data point | ARES API | CompanyData API |
|---|---|---|
| Legal name | ✓ | ✓ |
| IČO (registration number) | ✓ | ✓ |
| Registered address | ✓ | ✓ |
| Legal form & status | ✓ | ✓ |
| CZ-NACE industry code | ✓ | ✓ |
| Directors & statutory bodies | ✓ (VR endpoint) | ✓ |
| Financial statements as data | ✗ PDFs only | ✓ |
| Employee count | ✗ size bands only | ✓ |
| Email, phone & website | ✗ | ✓ |
| SIC & NACE codes | ✗ | ✓ |
| International records | ✗ | ✓ 365M+ worldwide |
Compare Access & Filters
ARES is built for one-by-one lookups. CompanyData is built for search, segmentation and bulk.
| Access / Search | ARES API | CompanyData API |
|---|---|---|
| Lookup by IČO | ✓ | ✓ |
| Search by name | ✓ | ✓ |
| Filter by CZ-NACE / industry | ✓ basic | ✓ |
| Filter by revenue or employees | ✗ | ✓ |
| Filter by region or city | ✗ | ✓ |
| Bulk export | ✗ separate XML dumps | ✓ |
| Stable rate limits | ✗ opaque IP bans | ✓ |
| Consistent JSON shape | ✗ per-register payloads | ✓ |
Compare Price
ARES is free for registry lookups. CompanyData adds the enrichment layer for a predictable credit price.
| Price comparison | ARES API | CompanyData API |
|---|---|---|
| Registry lookups | Free | From €0.02 per credit |
| Enriched records (financials, contacts) | ✗ not available | ✓ |
| Free trial | ✓ free service | ✓ free credits included |
| Guaranteed availability & support | ✗ | ✓ |
| One API for 200+ countries | ✗ | ✓ |
Try It Live
Search any Czech business and see the API response in real time.
ARES API Use Cases
KYB & Onboarding
Verify Czech counterparties by IČO. Check legal form, status and registry details automatically.
Lead Generation
Build prospect lists filtered by CZ-NACE code, region, revenue or business size across Czechia.
CRM Enrichment
Append registry details, industry codes, financials and contacts to your Czech accounts in bulk.
Risk & Compliance
Monitor status changes, liquidations and insolvencies in your Czech supplier base.
ARES API Pricing
Transparent, credit-based pricing. Start with a free trial.
Integration
Plug official register data into your stack in minutes.
REST APIJSONPython SDKJavaScriptSalesforceWebhooksZapier
Real-time responses with an average latency of <200ms. GDPR compliant with transparent data sourcing. Full documentation at companydata.com/api-docs.
More local trade register APIs
CompanyData covers official trade register data in 200+ countries through one API. Explore the register pages per country:
- CVR API (Denmark)
- Companies House API (UK)
- Sirene API (France)
- CNPJ API (Brazil)
- KRS API (Poland)
- SEC EDGAR API (USA)
- Handelsregister API (Germany)
- ABN Lookup API (Australia)
- MCA API (India)
- Bolagsverket API (Sweden)
- Zefix API (Switzerland)
- KBO API (Belgium)
- Brreg API (Norway)
- BORME API (Spain)
- CIPC API (South Africa)
- KVK API (Netherlands)
Frequently Asked Questions
The Czech business identification number: 8 digits, zero-padded, with a check digit. The VAT number (DIČ) is CZ followed by the IČO. CompanyData records carry the IČO as the registration number, so you can match records one-to-one with ARES.
No. Financial statements live in the Sbírka listin as PDF documents without an API. CompanyData provides revenue and employee figures as structured fields on Czech records, ready to filter and sort on.
Yes. Every Czech record carries the official CZ-NACE industry code next to international SIC and NACE codes, and you can filter searches by industry code to build targeted lists.
For registry-only lookups, ARES itself is fine. When you need enriched data, search filters, bulk export or guaranteed stability, CompanyData covers 3.4M+ Czech businesses with financials and contact data in one REST API that also spans 200+ other countries.
3.4M+ Czech business records, from s.r.o. to sole traders, updated continuously from the trade register and other official sources.