FS SR: Slovakia VAT register

The Financial Administration of the Slovak Republic publishes its list of subjects registered for VAT as open data and serves it through a keyed information lists API that answers for a single VAT number. It is the only register in the fallback path that needs an API key, and the only one whose list also carries subjects that are registered for VAT without being VAT payers.

FS SR is run by the Financial Administration of the Slovak Republic, and its data is published at opendata.financnasprava.sk. It is one of the 10 national registers Avatcado consults on the Pro and Business plans when VIES cannot answer for Slovakia, and it never replaces a VIES answer that does arrive. The national registry fallback guide covers the full precedence order.

What FS SR publishes

• The VAT identification number (IC DPH) of every subject registered for VAT in Slovakia, written with the SK prefix
• The registered name and the seat or place of business, with street, postcode and municipality as separate fields
• The organisation number (ICO) where one is assigned, which is a different identifier from the VAT number
• The type of registration under the VAT act (sections 4, 4b, 5, 6, 7 and 7a), the registration date and the date the type last changed

How Avatcado uses it

A Slovak fallback searches the registered-subjects list through the information lists API for the exact IC DPH, sending Avatcado's API key as a request header. A row carrying that number produces an answer served with source fssr, the registered name and an address assembled from the street, postcode and municipality fields. Every registration type counts as registered, because VIES confirms every type on the list. No matching row is a negative the register may not assert, so the request falls through to the cache, and a rejected key or an exhausted hourly allowance is treated as an outage of the register.

FS SR answers per number, so Avatcado calls it while your request is open, with a 10 second timeout. There is no snapshot to go stale (queried live on the request), so a fallback answer reflects the register as it stood at that moment. If the register is slow or down as well, the request falls through to the cache.

The rule that matters most is that a register can only ever confirm a registration. A miss, whether FS SR says not registered or simply has no record, is never turned into valid: false: the request falls through to the stored result instead. An answer that does come from here carries source: "fssr" and source_status: "fallback", and no consultation_number field at all, because only VIES issues those.

What a FS SR answer contains

Data quirks worth knowing

• The VAT register list behind the API is republished every morning, so an answer reflects the previous day
• Every registration type on the list counts as registered, including section 7 and 7a registrations that VIES also confirms
• Keyed API with an allowance of 1,000 requests per hour
• Subjects registered under sections 7 and 7a are on the list but are not VAT payers: they registered because they acquire goods or services from other member states, and VIES confirms their numbers all the same
• The list behind the API is republished every morning, so a lookup made during the day reflects the previous day's state even though the API itself answers on the request
• A VAT group registered under section 4b holds one IC DPH for all of its members, so an answer for such a number describes the group rather than the individual company
• The companion list of payers with grounds for deregistration is not consulted: those subjects stay registered until the authority acts, and VIES keeps confirming them

Try it

Validating a Slovakia VAT number takes the same call whichever source answers it. This one uses SK2020273893, a real registered number:

curl "https://api.avatcado.com/v1/validate?vat_number=SK2020273893" \
  -H "Authorization: Bearer avat_live_your_api_key"

import Avatcado from "@avatcado/node";

const avatcado = new Avatcado("avat_live_your_api_key");
const { data, error } = await avatcado.vat.validate({
  vatNumber: "SK2020273893",
});

if (data?.meta.source === "fssr") {
  // VIES was unavailable; FS SR confirmed the registration.
  console.log(data.meta.source_status); // "fallback"
}

On an ordinary day that answer comes from VIES, with source_status: "live". Only when VIES cannot answer for Slovakia does FS SR step in, and then meta.source_status reads "fallback" and meta.source reads "fssr". The register fallback is included in the Pro and Business plans; the free tier covers 500 validations per month from VIES and the cache. Get an API key or read the API documentation.

Frequently asked questions

Keep reading

• Slovakia VAT number format and validation
• Country coverage: what answers every country Avatcado validates
• All 10 national VAT registers
• VIES Down? How the National Registry Fallback Works
• VIES Downtime: Why It Happens and How to Handle It
• VIES API Guide: REST Endpoint, SOAP & Integration