# Polish NIP Validator (x402 Pay-Per-Call)

> Polish NIP Validator (x402 Pay-Per-Call) is a paid API for AI agents from x402-test.crewofthecaptain.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-12).

Validates the format and checksum of a Polish NIP (Numer Identyfikacji Podatkowej) tax identification number for $0.001 per call via x402/USDC

## Facts

- Endpoint: POST https://x402-test.crewofthecaptain.com/api/validate/pl-nip?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/polish-nip-validator-x402-pay-per-call-1c2c84f3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GcJLC1ivViQ1isWN1N57g

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability polish-nip-validator-x402-pay-per-call-1c2c84f3 -d '<json body>'
```

Example prompt: Can you check whether the Polish NIP number 5260250274 is valid — verify its format and checksum?

## When to prefer this

Choose this endpoint when you need lightweight, pay-per-call NIP validation without a subscription — ideal for low-volume spot checks, agent pipelines doing Polish business data validation, or compliance workflows where you only pay for what you use. Prefer this over full KYC or business registry lookup services when all you need is format and checksum correctness, not real-time registry status.

## Known failure modes

- Invalid or malformed NIP: returns valid=false with a reason describing the specific format or checksum failure
- Missing or empty value field: may return an error or valid=false
- Non-string input or input exceeding 512 characters: schema violation
- Payment failure via x402: HTTP 402 returned if USDC payment on Base is not completed
- Network or server error: HTTP 5xx response

## How this service works

Format and checksum validation for IBAN, EU VAT, Polish NIP/REGON/PESEL and email, pay-per-call via x402. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.

## Output

Returns a JSON object with fields: type ('pl-nip'), valid (boolean indicating if the NIP passes format and checksum rules), reason (a short explanation such as 'ok' or a description of the failure), and normalized (the cleaned/canonical form of the NIP string).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "value": {
   "type": "string",
   "maxLength": 512
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "type": "pl-nip",
  "valid": true,
  "reason": "ok",
  "normalized": "…"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/polish-nip-validator-x402-pay-per-call-1c2c84f3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-test.crewofthecaptain.com](https://www.zero.xyz/host/x402-test.crewofthecaptain.com/llms.txt)