W System / Slovakia eFaktúra 2027 for invoicing software

Slovakia eFaktúra 2027 for invoicing software: what the UBL file must contain

In short: from 1 January 2027 Slovak VAT payers must send domestic B2B and B2G invoices as Peppol BIS Billing 3.0 UBL files through a certified provider (digitálny poštár), and every Slovak business must be able to receive them. EN 16931 validity is not enough: the Financial Administration's transposition (v1.12, 14 October 2026) makes both Peppol addresses mandatory as 0245:DIČ and requires addresses, IČO, legal form, tax point date and exemption codes that EN 16931 treats as optional. This page lists those fields, the timeline (including the proposed no-fines half-year), the invoice UUID rule, a builder checklist and a working example you can run.

Timeline

Date	What happens	Status
1 Jan 2026	Act 385/2025 Coll. in force; provider register opens; voluntary e-invoicing through certified providers	in force
21 Aug 2026	Financial Directorate endpoint receives tax data from e-invoices and confirms receipt to providers	live
15 Dec 2026	Certified providers must have proven automated reporting, or are removed on 1 January 2027	upcoming
1 Jan 2027	Domestic VAT payers must issue e-invoices to Slovak taxable persons and legal persons; everyone must be able to receive; issue within 15 days of the supply	law
1 Jan – 30 Jun 2027	No fines for late e-invoices or reporting errors; buyer-side reporting deleted (bill 1454)	proposal: passed first reading 6 Oct 2026, committees until mid-November
1 Jul 2030	EU ViDA stage: cross-border e-invoicing and reporting, 10-day deadline, control statement abolished	law

How an eFaktúra travels

Slovakia uses the Peppol five-corner model without clearance. Your software (corner 1) creates the UBL file and hands it to the seller's certified provider (C2). The provider delivers it over Peppol to the buyer's provider (C3, then the buyer, C4) and sends a Tax Data Document to the Financial Administration's access point (C5). Handing the invoice to the provider counts as the seller's reporting. There is no QR code, hash or tax-authority stamp. Every Slovak participant is registered in a central SMP as 0245: plus the 10-digit DIČ, and a receiver can have only one receiving provider per DIČ. The list of 16 October 2026 names 80 certified providers.

Fields Slovakia requires beyond EN 16931

From the Financial Administration's spreadsheet "Transpozície štandardu Peppol BIS v podmienkach Slovenskej legislatívy" v1.12 (xlsx), column "Povinná náležitosť faktúry podľa SK legislatívy". The last column is the W System check that flags it (see the example below).

BT	Field	EN 16931	Slovak transposition	Check
BT-34, BT-49	Seller and buyer electronic address	0..1 in EN 16931	Mandatory (1..1). Slovak participants use scheme 0245 plus the 10-digit DIČ (the digits after 'SK' in the IČ DPH), not 9950 + VAT number.	SK-FS-02 to 06
BT-35, BT-37, BT-38	Seller street, city, postal code	0..1	Required: the VAT Act (s. 74(1)(a)) needs the address on the invoice.	SK-FS-07
BT-50, BT-52, BT-53	Buyer street, city, postal code	0..1	Required (s. 74(1)(b)).	SK-FS-08
BT-30, BT-47	Seller / buyer legal registration id (IČO)	0..1	Conditionally required: give it if an IČO has been assigned (Commercial Code s. 3a), with a scheme id from the ICD list.	SK-FS-09, 11
BT-33	Seller additional legal information	0..1	Conditionally required: legal form plus the register entry (court, section, insert number), e.g. 'Spoločnosť s ručením obmedzeným, zapísaná v Obchodnom registri Okresného súdu Žilina, oddiel Sro, vložka č. …'.	SK-FS-10
BT-7 / BT-8	Tax point date (DUZP) / its code	0..1	BT-7 is required when the supply date is known and differs from the issue date (s. 74(1)(d)); BT-8 is not used in Slovakia.	SK-FS-12, 13
BT-120, BT-121	VAT exemption reason text / code	conditional	FR SR recommends the VATEX code (BT-121) first, with BT-120 as the explanation; text is needed where the Act asks for specific wording (e.g. reverse charge).	SK-FS-15, 16
BT-3	Invoice type code	1..1	Corrections: credit note (381) plus a new invoice. Type 384 (corrected invoice) is being prepared with OpenPeppol and is not recommended yet.	SK-FS-17

Recent versions of the transposition: v1.10 corrected the cardinality of BT-31/BT-48, v1.11 reworded BT-116/BT-117 and fixed their calculation, v1.12 (14 October 2026) removed an erroneous text at BT-25. Check the Financial Administration page for the current version before you release.

VAT category and VATEX for Slovak cases

The FR SR FAQ (October 2026 edition, part III) says the category follows the legal regime of the supply, not the VAT amount: 0 € VAT is not automatically category Z. Selected rows of its mapping:

Slovak VAT Act / case	VAT category	VATEX (BT-121)
s. 27 (23 %, 19 %, 5 %)	S	–
s. 28 postal services	E	VATEX-EU-132-1A
s. 37 insurance, s. 38 real estate, s. 39 financial services	E	VATEX-EU-135-1
s. 43 intra-EU supply of goods	K	VATEX-EU-IC
s. 47 export outside the EU	G	VATEX-EU-G
s. 69 reverse charge	AE	VATEX-EU-AE
Not subject to VAT	O	VATEX-EU-O
Genuine zero rate set by law	Z	–

S and O cannot be mixed on one invoice (BR-O-11). The FAQ recommends two invoices, or category E with the text "outside the scope of tax" in BT-120 while EN 16931 is being revised.

The invoice UUID

The transposition's note on BT-34 explains why the seller address is mandatory: access points identify each invoice by a UUID version 5. The name is BT-34 schemeID, BT-34, BT-3, BT-1, BT-2 joined by single spaces (UTF-8, date as YYYY-MM-DD), and the namespace is fixed: 3fd00464-9f15-52ce-8cdc-6dd374d5ad42. Change any of these fields and the invoice gets a new UUID. Two things to watch: the document says "leading and trailing zeros" should be removed, which reads like a slip for whitespace, and its worked example gives the namespace itself as the output. Compute the value with a standard UUIDv5 library, store it with the invoice to match status messages, and confirm with your provider that you get the same value.

Checklist for invoicing and ERP builders

Output Peppol BIS Billing 3.0 UBL (CustomizationID urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0) for invoices and credit notes.
Store the DIČ for every Slovak customer and supplier and write it as EndpointID schemeID="0245". Do not reuse old 9950 identifiers.
Make street, city and postal code mandatory for Slovak parties, store the IČO and the register entry, and print the legal form in BT-33.
Fill BT-7 (tax point date) whenever the supply date differs from the issue date; never send BT-8.
Map each exemption to a VATEX code (BT-121) and keep the legal wording in BT-120.
Handle corrections as credit note plus new invoice; watch for the 384 release.
Look up whether the customer can already receive: Peppol Directory search for 0245:<DIČ>.
Pick a certified provider (or certify yourself) and run the Slovak test suites on the Peppol Testbed.
Validate every outgoing file before it reaches the provider and show users which field to fix.

Example: create a Slovak e-invoice and see what is still missing

Disclosure: W System, which publishes this page, makes the e-invoice API used below. The API turns simple JSON into a Peppol BIS 3 UBL invoice, writes the 0245:DIČ endpoints from the Slovak VAT numbers, checks the result against the official CEN EN 16931 rules and, for Slovak sellers, runs field checks we wrote from the v1.12 transposition (ruleset SK-FS, warnings only). They are our reading of the published spreadsheet, not the official Slovak or Peppol schematron, and Peppol BIS specific rules are not run yet. The request uses placeholder companies and numbers.

curl -X POST https://api.wsystem.dev/einvoice/create \
  -H 'Content-Type: application/json' --data @invoice.json

invoice.json:

{
 "format": "peppol-bis3",
 "invoice_number": "2026-0142",
 "issue_date": "2026-10-19",
 "due_date": "2026-11-02",
 "currency": "EUR",
 "buyer_reference": "OBJ-77",
 "delivery_date": "2026-10-15",
 "seller": {
  "name": "Predajca s.r.o.",
  "vat_id": "SK1234567890",
  "street": "Hlavná 1",
  "city": "Bratislava",
  "postal_code": "81101",
  "country": "SK"
 },
 "buyer": {
  "name": "Kupujúci a.s.",
  "vat_id": "SK9876543210",
  "street": "Mlynská 2",
  "city": "Košice",
  "postal_code": "04001",
  "country": "SK"
 },
 "lines": [
  {
   "description": "Implementation services, October 2026",
   "quantity": 10,
   "unit": "HUR",
   "unit_price": 65,
   "vat_rate": 23
  }
 ],
 "payment": {
  "iban": "SK3112000000198742637541",
  "terms": "14 days"
 }
}

Real response from the live API on 19 October 2026 (the generated XML left out):

{
 "valid": true,
 "format": "peppol-bis3",
 "syntax": "UBL 2.1",
 "document_type": "ubl_inv",
 "totals": {
  "currency": "EUR",
  "line_total": "650.00",
  "vat_total": "149.50",
  "total_with_vat": "799.50",
  "payable": "799.50"
 },
 "errors": [],
 "warnings": [
  {
   "rule_id": "SK-FS-09",
   "severity": "warning",
   "ruleset": "SK-FS",
   "message": "Seller legal registration identifier (BT-30, the IČO) is conditionally required: give it if an IČO has been assigned.",
   "business_terms": [
    "BT-30",
    "BT-30-1"
   ],
   "fix": "Add the seller IČO in cac:PartyLegalEntity/cbc:CompanyID (with schemeID from the ICD list)."
  },
  {
   "rule_id": "SK-FS-10",
   "severity": "warning",
   "ruleset": "SK-FS",
   "message": "Seller additional legal information (BT-33) is conditionally required: legal form and the register entry (court, section, insert number) for registered businesses (Commercial Code s. 3a).",
   "business_terms": [
    "BT-33"
   ],
   "fix": "Example: 'Spoločnosť s ručením obmedzeným, zapísaná v Obchodnom registri Okresného súdu Žilina, oddiel Sro, vložka č. 12345/L' in cbc:CompanyLegalForm."
  },
  {
   "rule_id": "SK-FS-11",
   "severity": "warning",
   "ruleset": "SK-FS",
   "message": "Buyer legal registration identifier (BT-47, the IČO) is conditionally required if an IČO has been assigned.",
   "business_terms": [
    "BT-47",
    "BT-47-1"
   ],
   "fix": "Add the buyer IČO in cac:PartyLegalEntity/cbc:CompanyID if it has one."
  },
  {
   "rule_id": "SK-FS-13",
   "severity": "warning",
   "ruleset": "SK-FS",
   "message": "Delivery date 2026-10-15 differs from the issue date 2026-10-19 but BT-7 (tax point date, DUZP) is empty. In Slovakia BT-7 is required when it is known and differs from the issue date (VAT Act s. 74(1)(d)).",
   "business_terms": [
    "BT-7",
    "BT-72"
   ],
   "fix": "Add cbc:TaxPointDate (create: tax_point_date)."
  }
 ],
 "checked": {
  "xsd": true,
  "EN16931": true,
  "XRechnung": false,
  "PeppolBIS3": false,
  "SK_national": true
 },
 "notes": [
  "Built to the Peppol BIS Billing 3.0 structure and checked against EN 16931 only; Peppol-specific rules are not run yet."
 ],
 "slovakia": {
  "applies": true,
  "transposition": "FR SR Peppol BIS transposition v1.12 (2026-10-14)",
  "source": "https://www.financnasprava.sk/sk/podnikatelia/dane/dan-z-pridanej-hodnoty/e-faktura",
  "checks": "W System field checks from the FR SR transposition; not the official Slovak/Peppol schematron.",
  "seller_dic": "1234567890",
  "participant_id": "0245:1234567890",
  "invoice_uuid": "a034f064-540e-5cd8-85bf-007521ce8414",
  "invoice_uuid_input": "0245 1234567890 380 2026-0142 2026-10-19",
  "invoice_uuid_note": "UUIDv5 over 'BT-34 schemeID, BT-34, BT-3, BT-1, BT-2' joined by single spaces, namespace 3fd00464-9f15-52ce-8cdc-6dd374d5ad42, per the BT-34 note in the transposition. The access points (C2/C3) compute the official value; the published example in the document is inconsistent, so treat this as a cross-check."
 }
}

The file is EN 16931 valid, but four Slovak points are open: no IČO for either party, no legal form for the seller, and a delivery date four days before the issue date without a tax point date. Adding "company_id" to both parties, "legal_form" to the seller and "tax_point_date": "2026-10-15" clears them. To check files your own software produces, upload them in the free e-invoice validator (no key, runs the same checks) or call POST /einvoice/validate. GET /einvoice/route?id=SK… tells you whether a customer is in the Peppol Directory under 0245. Free for 20 calls a day per IP; details on the e-invoice validation API page. This is a technical check, not tax advice.

Questions and answers

When does e-invoicing become mandatory in Slovakia?

From 1 January 2027 Slovak VAT payers must issue domestic B2B and B2G invoices as structured e-invoices (EN 16931, in practice Peppol BIS Billing 3.0 UBL) sent through a certified delivery-service provider, and every Slovak legal person and entrepreneur must be able to receive them. The legal basis is Act 385/2025 Coll., which amends the VAT Act 222/2004. 2026 is a voluntary period.

Is there a grace period without fines in 2027?

Not yet in law. Government bill 1454 proposes that no fines are imposed for late e-invoices or reporting errors between 1 January and 30 June 2027, and drops the buyer's duty to report received invoices. Parliament passed it in first reading on 6 October 2026; committees have until mid-November. The duty to issue and receive from 1 January 2027 is not changed by the bill.

Which Peppol identifier does a Slovak company use?

0245 followed by the 10-digit DIČ (tax identification number), for example 0245:1234567890. The IČ DPH (VAT number) is 'SK' plus the same 10 digits. Earlier drafts used 9950 with the VAT number; the transposition changed that to 0245 in version 1.2, and the Peppol Authority SK requires 0245 for registration in the central SMP.

Does my invoicing software have to become a certified provider (digitálny poštár)?

No. The software creates the e-invoice; a provider certified by the Financial Directorate (80 on the list of 16 October 2026) delivers it over Peppol and sends the tax data to the Financial Administration. You can become a provider yourself (OpenPeppol membership, accreditation by the Peppol Authority SK, Slovak onboarding tests on the Peppol Testbed) or integrate with one.

Which fields does Slovakia require beyond EN 16931?

According to the Financial Administration's Peppol BIS transposition v1.12 (14 October 2026): both electronic addresses (BT-34, BT-49) are mandatory, seller and buyer street, city and postal code are required, the IČO (BT-30, BT-47) and the seller's legal form and register entry (BT-33) are required when they exist, BT-7 tax point date is required when it differs from the issue date, and exemptions need the VATEX code and, where the Act requires wording, a reason text.

What is the Slovak invoice UUID?

Access points identify each invoice with a UUID version 5 computed from BT-34 scheme, BT-34 value, BT-3, BT-1 and BT-2 joined by single spaces, in the fixed namespace 3fd00464-9f15-52ce-8cdc-6dd374d5ad42. The access points compute it; software can compute the same value to match status messages. The worked example in the transposition shows the namespace itself as the output, so test against your provider.

Can I keep sending PDF invoices to Slovak customers?

Not for in-scope domestic supplies from 1 January 2027: a PDF is not an eFaktúra, and EDIFACT does not qualify either. Exempt supplies, simplified invoices (up to EUR 100, or eKasa receipts up to EUR 400) and cross-border supplies stay outside the domestic regime until the EU ViDA stage on 1 July 2030.

Sources

Checked against the Financial Administration documents (transposition v1.12, FAQ October 2026, provider list 16 October 2026) on 19 October 2026.

Facts checked 2026-10-19. W System is the maker of this product. Not affiliated with the European Commission. Not legal or tax advice.