About this API
YTJ (Yritys- ja yhteisötietojärjestelmä) is the Finnish business information system — a joint register of the PRH trade register and the tax administration. The avoindata API exposes data for every Finnish company by Business ID (Y-tunnus), and supports search by name.
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 Finnish company by Business ID — name, legal form, address, industry, status and name history. Companies can also be searched by name.
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?
PRH (Finnish Patent and Registration Office, Patentti- ja rekisterihallitus). Full documentation is available at avoindata.prh.fi.