In brief
- ARES is run by the Czech Ministry of Finance; it searches across several registers and its data is for information only.
- RES is kept by the Czech Statistical Office; it holds the address, legal form, activity and employee band of every Czech subject.
- Use ARES to check one company including VAT, the RES open data for the full list.
- The ARES API is limited to 500 queries a minute.
Anyone in Slovakia who needs data on a Czech customer runs into two abbreviations that sound almost the same. They are not two names for one thing.
ARES: search across several registers
ARES (Administrativní registr ekonomických subjektů) is run by the Czech Ministry of Finance, which describes it as an information system for searching economic subjects — not a register that creates data itself. It takes data from other sources:
- primary ones — for example the public register (the commercial register kept by the courts), the trade register and the Czech Statistical Office's RES,
- secondary ones — for example VAT payer registers, subsidy databases and insolvency data.
The ministry states explicitly that all information from ARES is for information only. ARES has a public API; under the ministry's terms a user must not send more than 500 queries a minute, and automated downloading of the database may be blocked.
RES: the Czech Statistical Office's register
RES (Registr ekonomických subjektů) is kept by the Czech Statistical Office under § 20 of Act No. 89/1995 Coll. on the State Statistical Service. It holds selected data on every economic subject based in the Czech Republic — mainly registered address, legal form, classification by economic activity and by number of employees. From 1 January 2026 activities follow the CZ-NACE 2025 classification.
The Statistical Office also publishes RES as open data — the full file for download. RES holds no statutory bodies, shareholders or VAT status; those are in other registers, which ARES gives you access to.
Which to use
- Checking one company, including VAT or commercial register details: ARES.
- The full list of Czech companies, for search in your application or analysis by sector: the RES open data.
- Bulk queries through the ARES API: mind the 500-queries-a-minute limit — the ministry reserves the right to block automated downloading of the database.
Czech companies in Apino
Apino takes the RES open data from the Czech Statistical Office. We check for a new file daily and load it when it is published. Czech companies are searched through the same API and in the same format as Slovak ones — add the parameter countries=SK,CZ.
As of 23 September 2026 we provide RES data for Czech companies. VAT status, the reliability index and e-invoicing readiness cover Slovak companies only.