About this API
ARES (Administrativní registr ekonomických subjektů) is the Czech equivalent of a combined REGON and CEIDG — it registers every Czech economic entity, aggregating data from several source registers (commercial, trade licensing, craft and others) under a single IČO number.
Frequently asked questions
Do I need an API key?
No, the API is fully public and free — no registration, no key required.
What data does this API return?
Registry data for a Czech company by IČO number — name, registered address, legal form, status and other basic data, aggregated from several Czech source registers.
Can this API be called directly from a browser?
Yes — the API returns a CORS header allowing calls from any domain, so it works directly from frontend code (hence the live "Try it" button above).
Who runs this API?
The Ministry of Finance of the Czech Republic. Full documentation is available at ares.gov.cz.