Build a KYC Workflow for European Businesses with One API

What KYC means for B2B platforms

Know Your Customer (KYC) in a B2B context means verifying that a business is real, active, and who they claim to be. For European businesses, this involves checking:

• Company identity: does this SIRET/SIREN exist? Is the company active?
• Tax status: is the VAT number valid? Is the company VAT-registered?
• Banking details: is the IBAN valid? Which bank? Is it SEPA-compatible?

Most platforms do this manually or with multiple services. The European Business API combines all three checks in one place.

The three-step verification

Step 1: Verify the company (SIRET)

For French businesses, validate the SIRET and retrieve company details:

import httpx

API_KEY = "your_api_key"
HEADERS = {"X-API-Key": API_KEY}

def verify_company(siret: str) -> dict:
    r = httpx.get(
        f"https://frenchbusinessapi.com/sirene/siret/{siret}",
        headers=HEADERS
    )
    if r.status_code != 200:
        return {"valid": False, "reason": "SIRET not found"}

    data = r.json()
    if not data.get("actif"):
        return {"valid": False, "reason": "Company is inactive/closed"}

    return {
        "valid": True,
        "name": data["denomination"],
        "address": f"{data['adresse_ligne1']}, {data['code_postal']} {data['ville']}",
        "naf": data["code_naf"],
        "activity": data["libelle_naf"],
    }

This immediately tells you if the company exists, is active, and what they do. See our SIRET lookup guide for more details.

Step 2: Validate VAT number

For intra-EU transactions, validate the VAT number via VIES:

def verify_vat(vat_number: str) -> dict:
    r = httpx.get(
        f"https://frenchbusinessapi.com/vat/validate/{vat_number}",
        headers=HEADERS
    )
    data = r.json()
    return {
        "valid": data["valid"],
        "vies_checked": data["vies_available"],
        "company_name": data.get("company_name"),
        "country": data["country_code"],
    }

A valid VAT number confirms the business is VAT-registered and gives you their official name and address from VIES. See our VAT validation guide.

Step 3: Verify IBAN

Before setting up payment, validate the customer's bank details:

def verify_iban(iban: str) -> dict:
    r = httpx.get(
        f"https://frenchbusinessapi.com/iban/validate/{iban}",
        headers=HEADERS
    )
    data = r.json()
    return {
        "valid": data["valid"],
        "bank": data.get("bank_name"),
        "bic": data.get("bic"),
        "sepa": data.get("sepa_member"),
    }

A valid IBAN with SEPA membership means you can process payments via SEPA credit transfer or direct debit. See our IBAN validation guide.

Putting it all together

A complete onboarding verification function:

def onboard_customer(siret: str, vat_number: str, iban: str) -> dict:
    results = {
        "company": verify_company(siret),
        "vat": verify_vat(vat_number),
        "iban": verify_iban(iban),
    }

    # Cross-check: company name from SIRET should match VIES
    all_valid = all([
        results["company"]["valid"],
        results["vat"]["valid"],
        results["iban"]["valid"],
    ])

    results["status"] = "approved" if all_valid else "review_required"
    return results

# Usage
result = onboard_customer(
    siret="35600000000048",
    vat_number="FR73356000000",
    iban="FR7630006000011234567890189"
)
print(result["status"])

Three API calls, one status. The entire verification takes under 2 seconds.

Red flags to watch for

• SIRET active but VAT number invalid: the company exists but isn't VAT-registered. Could be a dormant entity.
• Company name mismatch: the name from SIRET doesn't match the name from VIES. Possible identity issue.
• IBAN in a different country than the company: a French company with a Romanian IBAN is unusual (not necessarily fraudulent, but worth flagging).
• SIRET recently created: a company created days ago trying to place a large order deserves extra scrutiny.

Automating the flow

For high-volume onboarding (marketplace sellers, supplier registration), wrap the verification in an async pipeline:

import asyncio

async def verify_batch(customers: list[dict]) -> list[dict]:
    results = []
    for c in customers:
        result = onboard_customer(c["siret"], c["vat"], c["iban"])
        results.append({"customer": c["name"], **result})
        await asyncio.sleep(0.1)  # Respect rate limits
    return results

Beyond France

The VAT and IBAN endpoints cover all EU countries. For company lookup outside France, you'll need country-specific registries. But VAT + IBAN verification works across the entire EU with the same API calls.

Next steps

• Get your free API key, 100 requests/day
• API documentation
• Related: Business days calculator, Currency conversion