API to check the SIREN and VAT numbers on your e-invoices

Why check the numbers before the invoice

This page shows how to check these numbers with an API call before issuing an invoice or booking a supplier's, with examples in curl, JavaScript, Python, PHP and Ruby.

E-invoicing is being introduced in France in stages: every company must be able to receive electronic invoices from September 2026, and issuing extends to SMEs and micro-businesses from September 2027. The official calendar is explained on impots.gouv.fr (in French). The customer's SIREN becomes an item on the invoice: see what e-invoicing changes for the SIREN and the list of mandatory items.

Two moments lend themselves to an automatic check. When issuing, you check the buyer: the number exists, the company is active, the SIRET and the VAT number point to the same company. When receiving, you check the seller before booking and paying, which also lowers the risk of a fake invoice.

One call for the SIRET and the VAT number

The GET /v2/validate route takes a global identifier, a SIRET, a VAT number, or several at once. Each check comes back with its result, and valid is true only if every check passes. The API key goes in the X-API-Key header.

curl "https://api.jsonpage.com/v2/validate?siret=55203253400646&vat=FR27552032534" \
  -H "X-API-Key: $JSONPAGE_API_KEY"

Response (excerpt):

{
  "data": {
    "valid": true,
    "checks": [
      { "code": "siret_format", "ok": true, "value": "55203253400646" },
      { "code": "siret_key", "ok": true, "value": "55203253400646" },
      { "code": "vat_format", "ok": true, "value": "FR27552032534" },
      { "code": "identifiers_match", "ok": true, "value": "FR-552032534" },
      { "code": "company_exists", "ok": true, "value": "FR-552032534" },
      { "code": "company_active", "ok": true, "value": "active" },
      { "code": "vat_registered", "ok": true, "value": "valid" }
    ],
    "company": { "id": "FR-552032534", "name": "DANONE", "status": "active" }
  }
}

Spaces, dots and hyphens are ignored in the SIRET and the VAT number, so you do not need to clean the input before the call. VAT numbers of every European Union country are accepted, not only French ones.

Reading the result and deciding

Do not stop at valid: the checks list says which check failed, and so what to ask your counterpart.

For a batch of numbers, for example a whole customer file before the first invoicing run, the Customer file page does the check without any programming, and the method to clean a customer file details the steps.

Code examples

The same check in four languages, to plug into your invoicing software or ERP. The key is read from an environment variable: never put it in a page or in an application distributed to users.

JavaScript

async function checkParty(siret, vat) {
  const url = new URL("https://api.jsonpage.com/v2/validate");
  url.searchParams.set("siret", siret);
  url.searchParams.set("vat", vat);
  const res = await fetch(url, { headers: { "X-API-Key": process.env.JSONPAGE_API_KEY } });
  if (!res.ok) throw new Error("HTTP " + res.status);
  const { data } = await res.json();
  const failed = data.checks.filter((c) => !c.ok).map((c) => c.code);
  return { valid: data.valid, failed, company: data.company };
}

Python

import os
import requests


def check_party(siret, vat):
    r = requests.get(
        "https://api.jsonpage.com/v2/validate",
        params={"siret": siret, "vat": vat},
        headers={"X-API-Key": os.environ["JSONPAGE_API_KEY"]},
        timeout=10,
    )
    r.raise_for_status()
    data = r.json()["data"]
    failed = [c["code"] for c in data["checks"] if not c["ok"]]
    return data["valid"], failed, data["company"]

PHP

function checkParty(string $siret, string $vat): array
{
    $url = "https://api.jsonpage.com/v2/validate?" . http_build_query(["siret" => $siret, "vat" => $vat]);
    $context = stream_context_create(["http" => [
        "header" => "X-API-Key: " . getenv("JSONPAGE_API_KEY"),
        "timeout" => 10,
    ]]);
    $body = file_get_contents($url, false, $context);
    if ($body === false) {
        throw new RuntimeException("Request failed");
    }
    $data = json_decode($body, true)["data"];
    $failed = array_column(array_filter($data["checks"], fn ($c) => !$c["ok"]), "code");
    return [$data["valid"], $failed, $data["company"]];
}

Ruby

require "net/http"
require "json"

def check_party(siret, vat)
  uri = URI("https://api.jsonpage.com/v2/validate")
  uri.query = URI.encode_www_form(siret: siret, vat: vat)
  req = Net::HTTP::Get.new(uri, "X-API-Key" => ENV.fetch("JSONPAGE_API_KEY"))
  res = Net::HTTP.start(uri.host, uri.port, use_ssl: true) { |http| http.request(req) }
  raise "HTTP #{res.code}" unless res.is_a?(Net::HTTPSuccess)

  data = JSON.parse(res.body)["data"]
  failed = data["checks"].reject { |c| c["ok"] }.map { |c| c["code"] }
  [data["valid"], failed, data["company"]]
end

What the API does not do

The API checks numbers and the company they point to. It does not validate the invoice file (its structure, its fields, its compliance with the required format), does not send the invoice to a platform and does not replace the advice of your accountant. A VAT number reported as "not verifiable for now" is not a wrong number: try again later.

On volume, routes are limited per minute; beyond that the answer is 429 with a Retry-After header: wait that long before retrying. For a large batch, the batch route (100 companies per call) cuts the number of calls. See the documentation.

Keep reading

• E-INVOICINGFrance e-invoicing 2026: the list of mandatory invoice mentionsChecklist of French invoice mentions and the four new ones of the reform: customer SIREN, delivery, nature of operation, debits.
• INVOICINGCan your French customer receive e-invoices?Look up a French customer's approved platform in the official directory, and what the 2026-2027 timetable requires.
• E-INVOICINGFrance e-invoicing 2026: why your customers' SIREN becomes mandatoryThe four new mandatory mentions, the 2026-2027 timeline and how to verify your customers' SIREN numbers.
• APIIntra-EU VAT Number Verification API in JSONVerify a VAT number in one call: format, company, valid or invalid status. France, Belgium, Switzerland, Norway, Finland, Latvia, Sweden, Estonia, Lithuania. Fixed pricing.