Validate a national identity, tax or company registration number against its cou
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.
Answeringour last check, 2026-09-29
1 of 1checks answered this week
30 msmedian answer time
$0.05listed price per call
$0.05price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://api.duoleads.com/v1/id/national
| Category | Company and compliance |
|---|---|
| Provider host | api.duoleads.com |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-09-29 | valid payment request | 402 | $0.05 | 30 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"country": "NL",
"kind": "bsn",
"value": "111222333"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"country": {
"description": "ISO 3166-1 alpha-2 country code, case-insensitive. One of the 23 supported countries.",
"maxLength": 16,
"type": "string"
},
"kind": {
"description": "Identifier type for that country, e.g. bsn, nif, cf, cpf.",
"maxLength": 32,
"type": "string"
},
"value": {
"description": "The identifier. Separators (space . - /) are stripped before checking.",
"maxLength": 64,
"type": "string"
}
},
"required": [
"country",
"kind",
"value"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"data": {
"type": "object"
},
"meta": {
"properties": {
"computed_at": {
"type": "string"
},
"deterministic": {
"type": "boolean"
},
"disclaimer": {
"type": "string"
},
"price_usd": {
"type": "string"
},
"request_id": {
"type": "string"
},
"sources": {
"type": "array"
}
},
"required": [
"request_id",
"computed_at",
"price_usd",
"deterministic",
"disclaimer"
],
"type": "object"
},
"ok": {
"const": true,
"type": "boolean"
},
"route": {
"type": "string"
},
"version": {
"type": "string"
}
},
"required": [
"ok",
"route",
"version",
"data",
"meta"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}