Your ERP is centralised at headquarters. Your Polish subsidiary just went live under KSeF. Your accounting team in Budapest is reporting invoices to the Hungarian tax authority in real time. And your CFO in Bucharest is receiving penalties because your invoices are not flowing through the ANAF portal. Welcome to the reality of e-invoicing in Central and Eastern Europe.
These countries have moved ahead of Western Europe on fiscal digitalisation — not out of ideological commitment to technology, but because they needed to reduce VAT fraud, which was endemic through the 2010s. The result: Poland, Hungary, and Romania now impose mandatory e-invoicing regimes that most international ERP deployments simply did not anticipate. This guide maps the obligations country by country, with the technical parameters your ERP must master before processing a single invoice in these territories.
Context: Why Central and Eastern Europe Led on E-Invoicing
VAT Fraud as the Trigger for Regulatory Innovation
Poland, Hungary, and Romania were among the EU member states with the highest VAT Gap rates — the difference between theoretical and actually collected VAT — through the 2010s. The European Commission estimated Poland’s VAT Gap at over 25% of theoretical VAT in 2015 (European Commission, VAT Gap Report). The policy response: impose real-time reporting or centralised clearance to make fraud structurally harder.
The ViDA Directive as EU-Wide Convergence by 2030
The ViDA directive (VAT in the Digital Age), adopted in April 2025, extends digital reporting requirements across all EU member states (European Commission, ViDA adoption). Key milestones:
- 1 July 2030: mandatory digital reporting for all cross-border B2B intra-EU transactions, based on e-invoicing
- 1 January 2035: harmonisation of domestic digital reporting systems (including those established before 2024) with EU standards
This timeline means KSeF, RTIR, and e-Factura are not regional outliers destined to disappear — they are the forerunners of the model the entire EU will adopt. Groups treating them as “subsidiary problems” are underestimating the scope.
What This Means for Groups with Subsidiaries in Central and Eastern Europe
An ERP centralised in the UK or Ireland, configured for domestic invoicing models, cannot handle Polish, Hungarian, or Romanian flows the same way. Each country has its own system, its own XML schema, its own government API, its own transmission deadlines. ERP governance must shift from “one central instance” to “one central instance with local compliance connectors.”
Poland: KSeF, the Centralised Clearance Model
The Mandate in Effect Since February 2026
Poland has adopted a centralised clearance model unique in Europe: all B2B and B2G invoices must transit through the national KSeF platform (Krajowy System e-Faktur), managed by the Polish Ministry of Finance, before reaching the recipient.
The regulatory timeline:
- 1 February 2026: obligation for large taxpayers (turnover above PLN 200 million, approximately €47m) — confirmed by presidential signature on 27 August 2025 (poland-accounting.eu)
- 1 April 2026: extension to all other VAT-registered entities in Poland
- 1 January 2027: micro-entrepreneurs included, with financial penalties entering into force (2026 is a grace period without sanctions)
How KSeF Works Technically
The ERP creates the invoice, serialises it in FA(3) XML format (schema 3.0, which replaces FA(2) from early 2026), and sends it to the KSeF API with an authentication certificate or token. KSeF validates the schema, assigns a unique KSeF number, returns a UPO receipt (Urzędowe Poświadczenie Odbioru), and archives the invoice on the government side. The recipient retrieves it directly through their KSeF interface.
There is no email PDF, no Peppol network: everything goes through the state platform.
What the ERP Must Do
- Native KSeF API connector or middleware integration (authentication token management, retry on unavailability)
- Invoice generation in FA(3) XML format with all mandatory fields (including 100-field structured buyer data)
- Storage of the KSeF number in the accounting record (required for reconciliation and audit)
- Access to the KSeF portal for tracking and retrieving received invoices
SAP (via SAP Document and Reporting Compliance), Oracle (Tax Reporting Cloud), Sage, and Comarch offer native or certified connectors. Middleware platforms Pagero, Sovos, and Edicom also cover KSeF with a multi-country abstraction layer (Pagero, KSeF e-invoicing).
For a complete technical breakdown of KSeF and the associated ERP checklist, see our dedicated article: KSeF Poland 2026: Centralised E-Invoicing and What Your ERP Must Handle.
Hungary: RTIR, Real-Time Reporting Since 2021
A System Operational for Five Years
Hungary moved ahead of all its neighbours. Since 1 July 2021, RTIR (Real-Time Invoice Reporting, known as “Online Számla”) has been mandatory for all VAT-registered entities in Hungary, with no exceptions and no size threshold (EDICOM, Hungary RTIR).
The fundamental difference from the Polish model: RTIR is not a clearance system. The invoice is issued normally between sender and recipient. What is mandatory is the reporting of invoice data to the tax authority (NAV, Nemzeti Adó- és Vámhivatal) in real time — at the moment of issuance or within 24 hours.
Mandatory XML 3.0 Schema Since May 2025
NAV ended support for XML schema version 2.0 on 15 May 2025. All entities must now transmit invoice data in XML schema 3.0 (Global VAT Compliance, Hungary 2025). ERPs still configured on older schemas risk transmission rejections since that date.
From September 2025, NAV strengthened content validation for transmitted data: 15 new blocking error types were introduced (technical or content errors that prevent submission).
The Trap for Hungarian Subsidiaries in a Centralised Group
The rule applies to every VAT-registered entity in Hungary, regardless of where the ERP is hosted. A Hungarian subsidiary whose accounting is managed from a UK or European head office via a central ERP instance must still transmit every B2B invoice to NAV via RTIR. If the central ERP cannot send XML 3.0 flows to the Online Számla API, the subsidiary is non-compliant.
Penalties: up to HUF 1,000,000 (approximately €2,300) per unreported invoice, plus tax audits and the risk of losing VAT deductibility on the buyer’s side (DDDInvoices, Hungary RTIR).
Special Case: Energy Sector
From 1 July 2025, companies in the electricity and natural gas sectors became subject to a B2B e-invoicing obligation (not just reporting). This sector is serving as a pilot for a potential wider rollout.
Romania: e-Factura, Clearance Ahead of Schedule
The Romanian Timeline at a Glance
Romania imposed B2B e-invoicing by ANAF clearance from 1 January 2024, using a model close to the future French system. Chronological summary:
- January 2022: B2G obligation (public procurement)
- 1 January 2024: B2B obligation for all entities established or VAT-registered in Romania
- July 2024: full clearance mode — ANAF validates each invoice, affixes a digital seal, then transmits it to the recipient; end of the grace period, penalties now applicable
- 2025: extension to B2C (simplified regime) and self-employed
Format and Platform
The required format is UBL 2.1 XML conforming to ANAF specifications. Invoices are transmitted to the ANAF e-Factura platform via a dedicated API. After validation, the invoice receives an ANAF index number — this number is the legal proof that the invoice is valid. Without it, the invoice has no legal standing in Romania, even if signed and archived by the issuer.
Legal archiving period: 10 years.
Penalties: a Progressive Scale and a 15% Surcharge
Romania’s penalty regime is among the strictest in the EU:
For late or missing transmission (Global VAT Compliance, Romania 2025):
- Large companies: RON 5,000–10,000 (~€1,000–€2,000) per invoice
- Medium companies: RON 2,500–5,000 (~€500–€1,000) per invoice
- Small companies: RON 1,000–2,500 (~€200–€500) per invoice
For non-issuance through the system (since July 2024): a penalty of 15% of the invoice value — which, for significant B2B transactions, can amount to tens of thousands of euros per error (Sovos, Romania e-Factura).
Czech Republic and Other Countries: 2026 Status Update
Czech Republic: B2G Mandatory, B2B Awaiting ViDA
The Czech Republic mandates e-invoicing for public procurement via the NEN platform (Národní elektronický nástroj). However, there is currently no domestic B2B mandate. The Czech government has indicated it will use the ViDA directive to structure its B2B approach, without launching a parallel national system (Accace, Czech Republic e-invoicing). Groups with Czech subsidiaries can continue operating with traditional invoicing for domestic B2B flows until ViDA drives convergence.
Slovakia, Bulgaria, Slovenia
These countries are in consultation or progressive adaptation phases ahead of ViDA requirements. No B2B mandate is in force as of the time of writing (June 2026). To monitor: each member state’s ViDA transposition, with the first obligations applying from July 2030 for intra-EU flows.
ERP Impact and Recommendations for International Groups
Country-by-Country Audit: Three Levels of Obligation
Before configuring anything, map your entities:
| Country | Mandate in force | Model | Transmission deadline |
|---|---|---|---|
| Poland | KSeF (B2B + B2G) | Centralised clearance | Before delivery to recipient |
| Hungary | RTIR Online Számla (B2B + B2C) | Real-time reporting | Immediate or max 24h |
| Romania | e-Factura ANAF (B2B + B2G) | Clearance | Before delivery to recipient |
| Czech Republic | B2G only (NEN) | Public portal | N/A for B2B |
| Other CEE countries | Forthcoming (ViDA 2030+) | To be defined | — |
Native ERP Connector or Specialist Middleware?
Two approaches coexist across organisations:
1. Native ERP connector: SAP (Document and Reporting Compliance, or SAP DRC), Oracle (Tax Reporting Cloud), Sage, and other tier-1 vendors offer certified connectors for KSeF, RTIR, and e-Factura. This approach is coherent if your ERP is a tier-1 system with a documented international tax compliance roadmap. Verify that your specific version (S/4HANA, Oracle Cloud, etc.) has active connectors for each relevant country — on-premise versions nearing end-of-maintenance may have gaps.
2. Specialist middleware: Sovos, Pagero (ONESOURCE Pagero, formerly Thomson Reuters), Edicom, and Eesiflo offer multi-country platforms that sit between your ERP and government portals. The advantage: a single partner manages compliance across 10 to 80 jurisdictions, absorbing regulatory updates (schema changes, new NAV validations, etc.) without touching your core ERP. The additional licence cost is real but often lower than maintaining a native connector per country.
For a group with three CEE subsidiaries and a centralised ERP, specialist middleware is generally the fastest to deploy and the lowest-risk option for operational continuity.
8-Point Checklist for Groups with Central and Eastern European Subsidiaries
Before validating your invoicing system’s compliance across these countries, answer these questions:
- Poland: does your ERP generate FA(3) XML and have a KSeF API connector with token management?
- Poland: is the KSeF number stored in each invoice record in the ERP?
- Hungary: does your ERP transmit invoice data in XML schema 3.0 to the Online Számla API?
- Hungary: is the transmission delay under 24 hours from invoice issuance?
- Romania: does your ERP transmit invoices to the ANAF API before delivery to the recipient, and store the returned ANAF index number?
- Romania: is your archiving system configured for 10-year retention?
- Multi-country: if a government portal becomes unavailable (planned maintenance or incident), what queue-and-retry mechanism exists in your ERP or middleware?
- Governance: who in your organisation is responsible for monitoring schema updates and new regulatory validations in each country?
If you cannot answer “yes” with supporting evidence for each of these points, your group is exposed to penalties in at least one country.
What to Watch in 2026-2027
Poland — grace period ends 1 January 2027: financial penalties for KSeF non-compliance will take effect from Q1 2027. If your Polish subsidiary is not compliant before end of 2026, your risk window is very short.
Hungary — new NAV validations (already active since September 2025): the 15 blocking error types introduced can reject transmissions if data lacks consistency. Review the transmission logs for your Hungarian subsidiary.
ViDA — national transposition to monitor by country: each member state must transpose ViDA. Countries without a domestic system (Czech Republic, Slovakia, Bulgaria) will legislate between 2026 and 2029. A semi-annual regulatory watch is recommended for multi-country CEE groups.
Format convergence toward EN 16931: ViDA requires domestic systems to converge on the European EN 16931 standard by 2035. KSeF (FA(3)) and e-Factura (UBL 2.1) are already partially aligned. RTIR is a reporting system, not an exchange format — its architecture will need to evolve.
For further reading, see our overview of mandatory e-invoicing across Europe and its ERP impact and our mid-2026 status report on e-invoicing in France (PDP, PPF, e-reporting) — the French clearance framework shares the same logic as Romania’s, with its own operational specificities.
