Slovenia VAT Validation API
Validate Slovenia DDV ID numbers via REST API. Backed by EU VIES (real-time) — returns registration status, company name, and address in a single call.
Quick start
CURL
curl -H "Authorization: Bearer YOUR_API_KEY" \ http://localhost:3000/api/v1/validate/SI/SI12345678
Single validation
Validate one Slovenia VAT number. Returns full company details for valid numbers.
const res = await fetch(
'http://localhost:3000/api/v1/validate/SI/SI12345678',
{ headers: { 'Authorization': 'Bearer YOUR_API_KEY' } }
);
const data = await res.json();
/*
{
"valid": true,
"status": "active",
"company_name": "Example GmbH",
"address": "Musterstraße 1, Slovenia",
"country_code": "SI",
"vat_number": "SI12345678",
"cached": false,
"request_id": "req_01abc..."
}
*/Response format
{
"valid": true,
"status": "active",
"company_name": "Example Slovenia Ltd",
"address": "Musterstraße 1, Slovenia",
"country_code": "SI",
"vat_number": "SI12345678",
"cached": false,
"request_id": "req_01abc..."
}| Field | Type | Description |
|---|---|---|
| valid | boolean | true if the number is registered and active |
| status | string | "active", "inactive", "not_found", or "invalid_format" |
| company_name | string | null | Registered company name (where available from authority) |
| address | string | null | Registered address (where available from authority) |
| country_code | string | ISO 2-letter code — always "SI" for this endpoint |
| vat_number | string | The VAT number as sent in the request |
| cached | boolean | true if result served from cache (valid: 24h, invalid: 1h) |
| request_id | string | Unique request ID for support and audit logs |
Batch validation
Validate up to 25 numbers in a single POST request. Numbers are processed in parallel — ideal for onboarding flows and nightly reconciliation.
curl -s -X POST http://localhost:3000/api/v1/validate \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"numbers": [
{ "country": "SI", "vat": "SI12345678" },
{ "country": "SI", "vat": "SI12345679" }
]
}'[
{
"vat": "SI12345678",
"valid": true,
"status": "active",
"company_name": "Example Ltd",
"country_code": "SI",
"cached": false
},
{
"vat": "SI12345679",
"valid": false,
"status": "not_found",
"country_code": "SI",
"cached": false
}
]Error codes
| HTTP status | Meaning | Action |
|---|---|---|
| 400 | Bad request — malformed VAT format | Check the VAT format against the pattern below |
| 401 | Missing or invalid API key | Pass a valid Bearer token in the Authorization header |
| 404 | Country not supported | Check /vat-api for the full list of supported countries |
| 422 | Validation failed — invalid format | The number does not match the expected format |
| 429 | Rate limit exceeded | Back off and retry after the Retry-After header value |
| 503 | Upstream authority unavailable | VIES/authority is temporarily down — retry with exponential backoff |
Slovenia VAT format reference
| Property | Value |
|---|---|
| Country code (ISO) | SI |
| Local name | DDV ID (Davek na dodano vrednost Identifikacijska številka) |
| Format | SI + 8 digits |
| Regex | ^SI[0-9]{8}$ |
| Example | SI12345678 |
| Standard rate | 22% |
| Validation source | EU VIES (real-time) |
| VIES supported | Yes |
Slovenia is a small but strategically positioned EU market between Italy and Austria. The DDV ID (VAT ID) is 8 digits. Slovenia increased its standard VAT rate from 22% to 22% in recent years, maintaining one of the more moderate rates in the region.
Frequently asked questions
What does the TaxID API return for a Slovenia VAT validation?
For a valid Slovenia VAT number the API returns: `valid: true`, `status: "active"`, plus `company_name` and `address` where available from EU VIES (real-time). For invalid numbers it returns `valid: false` with a reason code. All fields are documented in the API reference.
How fast is the Slovenia VAT validation API?
Cached results (valid numbers are cached 24h, invalid 1h) respond in under 10ms. Uncached requests that require a live lookup via EU VIES (real-time) typically complete in 100–400ms. The `cached` field in the response tells you whether the result came from cache.
What is the Slovenia VAT number format?
Slovenia VAT numbers (DDV ID (Davek na dodano vrednost Identifikacijska številka)) follow the pattern: SI + 8 digits. A valid example is `SI12345678`. The TaxID API validates the format locally before making any live request, so malformed numbers fail instantly without consuming your quota.
Can I validate multiple Slovenia VAT numbers in one request?
Yes. The batch endpoint (POST /api/v1/validate) accepts up to 25 VAT numbers in a single request, processed in parallel. This is ideal for bulk onboarding flows, nightly reconciliation jobs, or importing customer lists. Each item in the response array maps 1-to-1 with your input array.
Start validating Slovenia VAT numbers
Free plan — 100 validations/month. No credit card required.
Integrate with your stack:
More Slovenia resources:
Validate VAT in other countries: