KRS (Poland)

GET/v0/pl/krs

Validates Polish National Court Register (Krajowy Rejestr Sądowy) numbers. A KRS number is a unique 10-digit sequential identifier assigned to entities registered in Poland. The input may be provided with or without leading zeros — the response always returns the canonical zero-padded 10-digit form. Optionally fetches live entity data from the official Polish government KRS API. The lookup first searches the Register of Entrepreneurs (P); if not found, it automatically tries the Register of Associations (S). The response indicates in which register the entity was found via the registry field.

Guides: Node.js · Python

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Query Parameters

Parameter	Type	Required	Description
value	string	Yes	The KRS number to validate. Accepts 1–10 digits (with or without leading zeros).
lookup	boolean	No	When `true`, performs a live lookup against the official Polish KRS government API and returns entity details.

Example Request

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/pl/krs?value=0000896246&lookup=true"

Response Fields

Field	Type	Description
valid	boolean	Whether the value is a valid KRS number
number	string	Canonical zero-padded 10-digit KRS number
krs	object	Live lookup result. Present only when `lookup=true`. See The `krs` object below.

The `krs` object

When the lookup failed (checked: false):

Field	Type	Description
checked	boolean	`false`
reason	string	`unavailable` — the government KRS API could not be reached

When the lookup succeeded (checked: true):

Field	Type	Description
checked	boolean	`true`
found	boolean	Whether the entity was found in either register
krs	string \| null	Canonical KRS number as returned by the government API
registry	string \| null	Register in which the entity was found: `P` — Register of Entrepreneurs (Rejestr Przedsiębiorców), `S` — Register of Associations (Rejestr Stowarzyszeń).`null` when `found` is `false`.
name	string \| null	Registered name of the entity
legalForm	string \| null	Legal form (e.g. `SPÓŁKA Z OGRANICZONĄ ODPOWIEDZIALNOŚCIĄ`)
nip	string \| null	Tax identification number (NIP)
regon	string \| null	Statistical identification number (REGON)
hasOppStatus	boolean \| null	Whether the entity holds Public Benefit Organisation (OPP) status
registeredAt	string \| null	Date of registration in the KRS (ISO 8601, YYYY-MM-DD)
dataAsOf	string \| null	Date the returned data is valid as of (ISO 8601, YYYY-MM-DD)
lastEntryAt	string \| null	Date of the most recent entry in the register (ISO 8601, YYYY-MM-DD)
address	object \| null	Registered address with fields: `city`, `voivodeship`, `street`, `houseNumber`, `flatNumber`, `postalCode`, `country`, `website`

Example Response

{
  "valid": true,
  "number": "0000896246",
  "krs": {
    "checked": true,
    "found": true,
    "krs": "0000896246",
    "registry": "P",
    "name": "CREACT.DEV SPÓŁKA Z OGRANICZONĄ ODPOWIEDZIALNOŚCIĄ",
    "legalForm": "SPÓŁKA Z OGRANICZONĄ ODPOWIEDZIALNOŚCIĄ",
    "nip": "5252859428",
    "regon": "388770013",
    "hasOppStatus": false,
    "registeredAt": "2021-04-21",
    "dataAsOf": "2026-01-15",
    "lastEntryAt": "2026-01-14",
    "address": {
      "city": "WARSZAWA",
      "voivodeship": "MAZOWIECKIE",
      "street": "UL. ŚWIĘTOKRZYSKA",
      "houseNumber": "30",
      "flatNumber": "63",
      "postalCode": "00-116",
      "country": "POLSKA",
      "website": "HTTPS://CREACT.DEV/"
    }
  }
}