Checking Polish companies from code: VAT, KRS, REGON, EU VAT (REST + Python + MCP)
If you invoice or onboard Polish companies, sooner or later you have to check two dull things that turn out to matter a lot: is this company actually a registered VAT payer, and is the bank account they gave you the one that's on the government's official white list ("Biała Lista")? Both of those affect whether you can deduct the cost and reclaim VAT, so it's not really optional. The annoying part is that the data lives in four different places: the Ministry of Finance, the KRS court register, GUS (the stats office), and the EU's VIES service. Each one has its own API and its own quirks. I got tired of gluing those together every time, so I wrapped them behind a few plain HTTP calls that return JSON. Full disclosure: skanfirmy.pl is mine. It's free, no key, no signup, and the web layer runs client-side with no tracking. Here's how you'd actually use it. REST: one GET, one JSON Cheapest thing you can do is check a NIP (the tax ID): curl https://skanfirmy.pl/nip/5260250995 You get back the VAT status (active, exempt, or not registered), the company details from the VAT register, and the accounts sitting on the white list. The paths: GET /nip/{nip} gives VAT status + white-list data for one NIP GET /nips/{list} takes several NIPs at once (comma-separated) GET /regon/{nip} returns data from the REGON register (GUS) GET /vies/{country}/{number} validates an EU VAT number, e.g. /vies/DE/811128135 It's a plain GET that returns JSON, so it drops into anything that can make an HTTP request: a cron job, a lambda, a CI step, whatever. Python requests and a few lines. This one raises if the company isn't an active VAT payer: import requests def check_vat ( nip : str ) -> dict : r = requests . get ( f " https://skanfirmy.pl/nip/ { nip } " , timeout = 10 ) r . raise_for_status () data = r . json () status = data . get ( " vatStatus " ) or data . get ( " status " ) if status != " Czynny " : # status comes back in Polish; compare against the raw value raise ValueError ( f " NIP { n