API documentation

Authentication

Every request carries your API key in the HTTP header:

Authorization: Bearer dck_live_…

Endpoint

POST https://data-checker.fr/api/v1/validate

Request body (JSON):

{
  "type": "email | phone | siret | iban",
  "value": "the value to check",
  "country": "FR"   // optional, for phone numbers
}

Each successful call spends 1 credit. The response is a 402 when the balance runs out, and a 401 when the key is missing or unrecognised.

Example (JavaScript)

const res = await fetch("https://data-checker.fr/api/v1/validate", {
  method: "POST",
  headers: {
    "Authorization": "Bearer dck_live_…",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({ type: "email", value: "contact@example.com" }),
});
const data = await res.json();
console.log(data.valid); // true | false

Responses by type

{
  "type": "email",
  "input": "contact@example.com",
  "valid": true,
  "syntaxValid": true,
  "domain": "example.com",
  "mxFound": true,
  "disposable": false,
  "roleBased": true,
  "reason": null,
  "credits_remaining": 99
}

{
  "type": "phone",
  "input": "06 12 34 56 78",
  "valid": true,
  "e164": "+33612345678",
  "national": "06 12 34 56 78",
  "international": "+33 6 12 34 56 78",
  "country": "FR",
  "type_line": "mobile",
  "credits_remaining": 98
}

{
  "type": "siret",
  "input": "55210055400021",
  "valid": true,
  "kind": "SIRET",
  "siren": "552100554",
  "nic": "00021",
  "formatted": "552 100 554 00021",
  "laPoste": false,
  "vatNumber": "FR96552100554",
  "vatKey": "96",
  "reason": null,
  "credits_remaining": 97
}

{
  "type": "iban",
  "input": "FR1420041010050500013M02606",
  "valid": true,
  "country": "FR",
  "countryName": "France",
  "sepa": true,
  "formatOk": true,
  "lengthOk": true,
  "formatted": "FR14 2004 1010 0505 0001 3M02 606",
  "bankCode": "20041",
  "bank": "La Banque Postale",
  "bic": "PSSTFRPP",
  "bban": { "banque": "20041", "guichet": "01005", "compte": "0500013M026" },
  "ribKeyValid": true,
  "credits_remaining": 96
}

On the siret type, the API checks the Luhn key — including the derogatory rule for La Poste SIRETs starting 356000000 —, returns the siren + nic split and derives the intra-community VAT number. These fields are computed from the number itself: the API does not check the company's existence against the INSEE register.

On the iban type, the response adds the country, SEPA membership, the formatted IBAN and, for a French IBAN, the BBAN split, the national RIB key check and the bank name when the institution code is recognised.

Error codes