---
title: "French SIREN/SIRET checksum validation (Luhn + La Poste exception), offline"
method: GET
path: "/v1/fr/siret-check"
---

# French SIREN/SIRET checksum validation (Luhn + La Poste exception), offline

`GET /v1/fr/siret-check`

## Request

- Base URL: `https://data.greeneris.io` (the document declares no server; this is the origin it was published from)
- URL: `https://data.greeneris.io/v1/fr/siret-check`
- Auth: none declared

Instant pre-validation of French company numbers before invoicing or costly Sirene API calls. Auto-detects SIREN (9 digits) vs SIRET (14 digits), applies the INSEE Luhn rule and the documented La Poste exception (356000000*: digit sum mod 5). Query: ?number=44306184100047 (spaces/dots/dashes tolerated). Returns valid, type, siren, nic and the rule applied. Pure offline computation, 1y cache.

## Query parameters

- `number` string, required

## Response `200`

Successful response

- unknown

---

[API](https://skmtc.dev/greeneris/apis/eu-verify.md) · [All operations](https://skmtc.dev/greeneris/apis/eu-verify/llms.txt) · [OpenAPI document](https://skmtc.dev/greeneris/apis/eu-verify/revisions/766cf4a67d8f?raw)