@m8t-jacob/polish-registry

A unified, fully typed TypeScript client for Polish company registries: the VAT whitelist ("Biała lista podatników VAT"), VIES (EU VAT number validation), and a roadmap for GUS/REGON.

• Strict TypeScript, ships dual ESM + CJS builds with .d.ts
• Single runtime dependency: @m8t-jacob/validate, used to validate NIP checksums before any network request is made
• Tree-shakeable; import the whole package or a single subpath
• Zero real network calls in tests — the test suite mocks fetch, so CI runs deterministically offline
• Honest about what isn't done yet: gus.ts is a documented stub, not a fake implementation (see Roadmap below)

Install

npm install @m8t-jacob/polish-registry

Quickstart

import { checkAccount, checkNip, checkVat } from '@m8t-jacob/polish-registry';

await checkNip('5252445767');
// { nip: '5252445767', name: '...', statusVat: 'Czynny', regon: '...', krs: '...', accountNumbers: [...], requestId: '...', found: true }

await checkAccount('10114020040000381203083904', '5252445767'); // true | false

await checkVat('PL', '5252445767');
// { valid: true, name: '...', address: '...', countryCode: 'PL', vatNumber: '5252445767', requestDate: '...' }

You can also import from a subpath if you only need one module, which keeps bundlers from pulling in the others:

import { checkNip, checkAccount } from '@m8t-jacob/polish-registry/whitelist';
import { checkVat } from '@m8t-jacob/polish-registry/vies';

Or use the PolishRegistry namespace if you prefer a single import:

import { PolishRegistry } from '@m8t-jacob/polish-registry';

await PolishRegistry.whitelist.checkNip('5252445767');
await PolishRegistry.vies.checkVat('PL', '5252445767');

API

VAT whitelist (whitelist)

Client for the Polish Ministry of Finance's "Biała lista podatników VAT" / "wykaz podatników VAT" public REST API (https://wl-api.mf.gov.pl, no API key required).

Function	Description
checkNip(nip, options?): Promise<WhitelistResult>	Looks up a NIP, returning name, VAT status, REGON/KRS, and bank accounts
checkAccount(account, nip, options?): Promise<boolean>	Whether a 26-digit bank account (NRB) is registered to a NIP

options.date (YYYY-MM-DD) queries the registry as of that date; it defaults to today. Both functions validate the NIP with isValidNip from @m8t-jacob/validate before making a network call, throwing RegistryError immediately for an invalid checksum.

interface WhitelistResult {
  nip: string;
  name: string | null;
  statusVat: string | null; // e.g. 'Czynny', 'Zwolniony', or null when not found
  regon: string | null;
  krs: string | null;
  accountNumbers: string[];
  requestId: string;
  found: boolean;
}

VIES (vies)

Client for the European Commission's VIES (VAT Information Exchange System) public REST API, used to validate EU VAT numbers.

Function	Description
checkVat(countryCode, vatNumber): Promise<ViesResult>	Validates an EU VAT number, returning name/address if available
EU_COUNTRY_CODES	The 27 accepted 2-letter codes (EL for Greece) plus XI (Northern Ireland)

interface ViesResult {
  valid: boolean;
  name?: string;
  address?: string;
  countryCode: string;
  vatNumber: string;
  requestDate: string;
}

Endpoint note: this package calls https://ec.europa.eu/taxation_customs/vies/rest-api/ms/{countryCode}/vat/{vatNumber}, the public REST API that succeeded the older SOAP checkVatService. It was manually confirmed reachable and returning the { isValid, requestDate, name, address, vatNumber } shape documented above as of 2026-07-13 (the same date this package's country list was cross-checked against the live GET .../rest-api/check-status endpoint). If the European Commission changes this endpoint, please open an issue.

Shared

Export	Description
RegistryError	Thrown by every client for invalid input, network failures, timeouts, or non-OK API responses; has an optional status
PolishRegistry	Convenience namespace: { whitelist, vies, gus }

Every request has a 10-second timeout (AbortSignal.timeout); a timed-out or failed request always surfaces as RegistryError, never an unhandled rejection with a different shape.

GUS/REGON (gus) — not yet implemented

getGusReport() is a stub that always throws RegistryError('GUS BIR client not yet implemented — see roadmap'). See Roadmap.

Roadmap

• GUS/REGON (BIR) client. GUS's "Baza Internetowa REGON" web service is SOAP-based (BIR1.1), requires a registered API key (sid) from https://api.stat.gov.pl, a stateful login/logout session, periodic keep-alives, and XML parsing of the report payloads embedded in the SOAP envelope. That's meaningfully more surface than the REST/JSON clients above, so it's deliberately left as a documented stub (src/gus.ts) rather than a half-working implementation. Tracked in GOOD_FIRST_ISSUES.md — contributions welcome.
• Retry/backoff for transient network failures on the whitelist and VIES clients.
• KRS (Krajowy Rejestr Sądowy) API client, once a stable public REST endpoint is confirmed.

🇵🇱 Po polsku

@m8t-jacob/polish-registry to zunifikowany, w pełni typowany klient TS do polskich rejestrów firmowych: Biała lista podatników VAT (API Ministerstwa Finansów), VIES (walidacja numerów VAT w UE) oraz zaślepka GUS/REGON wraz z jawnie opisanym planem (roadmapą) na przyszłość. Pakiet ma jedną zależność uruchomieniową — @m8t-jacob/validate — używaną do walidacji sumy kontrolnej NIP przed wysłaniem jakiegokolwiek zapytania sieciowego. Klient GUS/REGON (gus.ts) nie działa w tej wersji: BIR to usługa SOAP wymagająca klucza API i zarządzania sesją, co jest poza zakresem wersji 1.0 — funkcja getGusReport() zawsze rzuca RegistryError z jasnym komunikatem, zamiast udawać, że coś zwraca. Testy nie wykonują żadnych realnych zapytań sieciowych (mockowany fetch), dzięki czemu CI działa deterministycznie offline.

Contributing

Contributions are welcome! See CONTRIBUTING.md for the development workflow and GOOD_FIRST_ISSUES.md for ideas if you're looking for a place to start. This project follows the Contributor Covenant.

License

MIT © 2026 Jakub Jagiełło