Switzerland UID Validation API: Tax ID Checks for Swiss Businesses

Switzerland is not an EU member state and does not participate in VIES. Swiss businesses are identified by their UID (Unternehmens-Identifikationsnummer — business identification number), a 9-digit number prefixed with `CHE`. Swiss VAT is administered by the Federal Tax Administration (ESTV/AFC/AFC) and is called MWST/TVA/IVA depending on language. A business may have a UID without being MWST-registered — the TaxID API distinguishes between these cases.

Swiss UID / MWST Format

Format	Example	Notes
CHE + 9 digits	CHE123456789	Standard format — dashes and dots stripped
CHE-xxx.xxx.xxx	CHE-123.456.789	Display format — accepted, normalised automatically
CHE-xxx.xxx.xxx MWST	CHE-123.456.789 MWST	Full VAT registration number with MWST suffix

Validating a Swiss UID Number

typescriptlib/validate-ch-uid.ts

async function validateSwissUid(uidNumber: string) {
  // Normalise: strip spaces, dots, dashes, MWST suffix
  let normalised = uidNumber
    .replace(/[\s\.\-]/g, '')
    .replace(/MWST|TVA|IVA$/i, '')
    .toUpperCase();

  // Ensure CHE prefix
  if (!normalised.startsWith('CHE')) normalised = 'CHE' + normalised;

  const res = await fetch(
    `https://taxid.dev/api/v1/validate/CH/${normalised}`,
    { headers: { Authorization: `Bearer ${process.env.TAXID_API_KEY}` } }
  );

  return res.json();
}

// Usage:
const result = await validateSwissUid('CHE-123.456.789 MWST');
// or:
const result2 = await validateSwissUid('CHE123456789');

UID vs MWST Registration

Every Swiss company registered in the Commercial Register has a UID. Not every company with a UID is registered for MWST (Swiss VAT). A company only needs to register for MWST if their annual turnover exceeds CHF 100,000. The TaxID API returns `status: 'active'` only when the UID is active AND the company is registered for MWST. If the company has a valid UID but is not MWST-registered, it returns `status: 'inactive'`.

Note

Switzerland is not an EU member, so Swiss companies are third-country buyers for EU VAT purposes. EU reverse charge does not apply. If you sell goods to Swiss customers, apply your home country's export rules (typically zero-rate for goods, plus Swiss import VAT at the border). For digital services to Swiss B2C customers over CHF 100,000/year, you may need to register for Swiss VAT.

pythonvalidate_ch_uid.py

import os, re, requests

def validate_swiss_uid(uid_number: str) -> dict:
    # Strip spaces, dots, dashes, and MWST/TVA/IVA suffix
    normalised = re.sub(r'[\s\.\-]', '', uid_number).upper()
    normalised = re.sub(r'(MWST|TVA|IVA)$', '', normalised)
    if not normalised.startswith('CHE'):
        normalised = 'CHE' + normalised

    resp = requests.get(
        f'https://taxid.dev/api/v1/validate/CH/{normalised}',
        headers={'Authorization': f'Bearer {os.environ["TAXID_API_KEY"]}'},
        timeout=5,
    )
    resp.raise_for_status()
    return resp.json()

Related guides

Norway MVA validation guide

Norwegian VAT API integration

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