Polish Tax Identification Number

NIP Generator

Generates random NIP numbers with a correct check digit. Each number is structurally valid but not registered with any tax authority.

Generated numbers pass checksum validation but are not assigned to any real entity. For testing purposes only.

How many numbers to generate?

About the NIP generator

Use cases

NIP generators are useful in software development and QA testing — for populating test databases, verifying input validation logic, and checking how an application handles correctly formatted tax IDs. Because a real NIP is tied to an actual legal entity, generated numbers must not appear in any real transaction, registration, or official document.

How generation works

The generator produces a random 9-digit prefix and computes the modulo 11 check digit using the official weights [6, 5, 7, 2, 3, 4, 5, 6, 7]. If the computed remainder is 10, the prefix is discarded and a new one is drawn. The result passes the same checksum algorithm used by Polish tax offices, but is otherwise entirely random.

Important limitation

Generated NIP numbers are for testing only. They are not assigned to any real entity. Using them in tax filings, invoices, business registrations, or official documents is prohibited and may constitute fraud.

Generator API

Each generator is backed by a REST API endpoint. Send a GET request with optional parameters and get an array of structurally valid numbers in JSON format.

GET /api/v1/generate/nip?count=5

Host: polishdata.eu

// Response 200 OK

{

"data": [

{

"nip": "5261040828",

"formatted": "526-10-40-828"

}

],

"count": 5,

"type": "nip"

}

Explore API docs