Guide · Identifiers
SIREN vs SIRET vs NIF
Which identifier you should store — and why getting this wrong breaks your integration later.
TL;DR
| Identifier | Country | Length | What it identifies |
|---|---|---|---|
| SIREN | France | 9 digits | Legal entity (company) |
| SIRET | France | 14 digits | Establishment (office / branch) |
| NIF | Spain | 1 letter + 8 chars | Legal entity (company or person) |
| VAT | EU-wide | FR+11 / ES+9+1 / … | EU intra-community VAT |
SIREN — the French legal-entity ID
A SIREN is 9 digits assigned by INSEE at the moment a French legal entity is created. It is issued for every type of entity: commercial companies (SAS, SARL, SA…), sole traders (entreprise individuelle), associations, GIEs, SCIs, even government agencies.
Key property: SIREN is stable for life. The company can change its name, move address, convert from SARL to SAS — the SIREN never changes. That makes it the correct foreign key for your internal database.
SIRET — per-establishment ID
A SIRET is 14 digits: the 9-digit SIREN followed by a 5-digit NIC (Numéro Interne de Classement). Each physical establishment of the company has its own SIRET.
SIRET: 55203253400646
└───┬───┘└──┬──┘
SIREN NIC (establishment)
(9 digits) (5 digits)A micro-entrepreneur with one home office has one SIRET. A retail chain like Carrefour has hundreds of SIRETs under a single SIREN. The NIC is typically `00001` for the headquarters, and higher numbers as new branches open.
NIF — Spain's equivalent
The Spanish NIF (Número de Identificación Fiscal) follows a different format: one letter encoding legal form, followed by 8 characters (7 digits + 1 control character).
A = SA (Sociedad Anónima) B = SL / SRL (Sociedad Limitada) C = S. Colectiva D = Comandita F = Cooperativa G = Asociación / Fundación H = Comunidad de propietarios N = Entidad extranjera X/Y/Z = NIE (foreign individual)
NIF is issued by the Agencia Tributaria. Like SIREN, it is stable for the company's lifetime and never collides across sectors.
Which one should you store?
For France — always SIREN. Store SIRET only when you need per-establishment granularity (shipping, billing by branch, site-level compliance).
For Spain — NIF. No equivalent to SIRET exists; Spanish companies are identified at the legal-entity level only.
If you go pan-European: use a compound key of (country_code, local_identifier). The Prometiam API uses this pattern — every `/companies/search` call takes either `?nif=` (ES) or `?siren=` / `?siret=` (FR). The France company data API guide shows the SIREN lookup end to end.
Common mistakes
- Using VAT as primary key — VAT numbers can change (registration, deregistration). SIREN / NIF cannot.
- Storing only SIRET when you meant SIREN — leads to duplicates: a company with 3 branches creates 3 rows.
- Treating NIE as NIF for companies — NIEs are for individuals (foreign residents). A company with an NIE in the NIF field means the scraper incorrectly classified a sole trader as a corporate.
- Ignoring the Luhn-like checksum — both SIREN and NIF have check characters; validate them on input to catch typos.
FAQ
What is a SIREN number?
A SIREN is a 9-digit number that uniquely identifies a French legal entity (company, association, sole trader) across its entire lifetime. Issued by INSEE at incorporation, it never changes, even if the company changes name, address, or legal form.
What is a SIRET number?
A SIRET is a 14-digit number identifying a specific establishment (office, shop, warehouse) of a French entity. Format: 9-digit SIREN + 5-digit NIC. A company with one office has one SIRET; a chain with 50 stores has 50 SIRETs sharing the same SIREN.
What is a NIF in Spain?
The NIF (Número de Identificación Fiscal) is Spain's tax-identification number. For companies it is a letter plus 8 characters. The first letter encodes the legal form: A = SA, B = SL/SRL, F = cooperativa, G = asociación. For individuals the NIF matches the DNI or a NIE for foreigners.
Which identifier should I store?
Store the SIREN (France) or NIF (Spain) as your foreign key: they uniquely identify the legal entity and never change. Store SIRET only if you need per-establishment granularity, such as shipping addresses or branch-level billing.
Can I convert between SIREN and SIRET?
A SIRET always starts with its parent SIREN, so take the first 9 digits to get the SIREN. To go the other way you need to know which establishment: the 5-digit NIC suffix indicates it, with 00001 typically the headquarters.
Is a SIRET the same as a NIF?
No. The NIF is Spain's tax number. France identifies a company by its SIREN (9 digits) and an establishment by its SIRET (14 digits). They are used in different countries and are not interchangeable.
NIF or SIREN: which one do I need for which country?
Use the SIREN for a French company and the NIF for a Spanish one. Stored as the foreign key, each identifies the legal entity in its own country.
Which is longer, SIREN or SIRET?
The SIRET: 14 digits against 9 for the SIREN. The SIRET is the SIREN plus a 5-digit NIC for one establishment.
What is the UK equivalent of a SIREN?
The Companies House company number, an 8-character registration number whose prefix shows the legal form. See the guide on what Companies House is.
What are the SIREN equivalents in other countries?
Every register has its own identifier. The UK uses the company number, Ireland the CRO number and Spain the NIF. The free company identifier validator shows the format for each country.
How do I find the SIRET from a SIREN?
The SIREN gives the first nine digits only. The remaining five digits are the NIC of the establishment, so you need the list of establishments of that SIREN; the head office is the siège.
Query examples
# France by SIREN GET /companies/search?siren=552032534 # France by SIRET (returns the specific establishment) GET /companies/search?siret=55203253400646 # Spain by NIF GET /companies/search?nif=A28015865 # Fuzzy by name, scoped to country GET /companies/search?name=carrefour&country=FR