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Duo Data Utilities – National ID / Tax / Company Number Validator
x402
Duo Data Utilities – National ID / Tax / Company Number Validator is a paid API for AI agents from api.duoleads.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-02).
Validates a national identity, tax, or company registration number against its country's official checksum algorithm — structure and check-digit only, no registry lookup or personal data stored.
Price / call$0.05
Success—
StatusUnknown
How this service works
Validate a national identity, tax or company registration number against its country's official checksum rule. Covers 23 countries including NL BSN, ES NIF/NIE/CIF, IT codice fiscale, FR SIREN/SIRET, DE Steuer-ID, BE/PL/CZ national numbers, SE/NO/DK/FI personal numbers, BR CPF/CNPJ, AU ABN/TFN, UK NINo, IE PPS, US NPI/EIN. Structure and check digit only — no registry lookup, no personal data stored.
Output
Returns a JSON object with a `valid` boolean, optional `reason` string explaining any failure, the `normalised` (stripped) form, the `formatted` canonical form, the `algorithm` name used (e.g. elfproef-11), any `derived` fields extracted from the number, plus standard `meta` including request ID, timestamp, price, and deterministic flag.
Example use cases
KYC onboarding form validation
“A user just entered their Italian codice fiscale 'RSSMRA85M01H501Z' on our signup form — can you validate whether it passes the official checksum rules before we submit the form?”
Tax ID compliance check for invoicing
“Before I generate this invoice, can you verify that the French SIRET number '73282932000074' is structurally correct using the official Luhn check?”
Bulk CPF validation in Brazil
“I have a Brazilian CPF '123.456.789-09' from a new supplier — can you run it through the CPF checksum algorithm and tell me if it's valid and what the normalised form looks like?”
Technical details
Endpoint
GEThttps://api.duoleads.com/v1/id/national?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a fast, deterministic, offline-style checksum validation of a national ID or tax number — it covers 23 countries and explicitly makes no registry call, stores no personal data, and returns a normalised and formatted form alongside the validity result. Prefer it over full KYC or registry-lookup services when you only need structural correctness (e.g. for form validation, deduplication, or pre-screening before an expensive registry call).
Side effects
- Unsupported country code returns an error indicating the country is not in the 23 supported list
- Unknown `kind` for a given country returns a validation error
- Malformed or empty `value` field returns a structural error before checksum evaluation
- Network or gateway errors return HTTP 4xx/5xx with no validation result
- Payment failure (x402) blocks the request before any computation
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"data": {
"kind": "bsn",
"valid": true,
"reason": null,
"country": "NL",
"derived": {},
"algorithm": "elfproef-11",
"formatted": "111.222.333",
"normalised": "111222333"
},
"meta": {
"price_usd": "0.05",
"disclaimer": "Factual output of a deterministic computation over public data. Provided as is, with no warranty of accuracy, completeness or availability. Not investment, financial, legal, tax, medical or any other professional advice, and not a recommendation. Verify before relying on it. Terms: https://api.duoleads.com/terms",
"request_id": "01K6B7Q4ZC8H3F2M9WXR5TYN0D",
"computed_at": "2026-09-28T12:00:00.000Z",
"deterministic": true
},
"route": "/v1/id/national",
"version": "1.0.0"
}
}Tags
x402
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