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Spotlight PEPPOL BIS Billing 3.0 The EU e-invoicing mandate is here — France Sept 2026, Belgium Jan 2026, Germany 2025.

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Serbia — e-invoicing through the SEF (e-Faktura)

Serbia has centralised the issuing and receipt of invoices on the SEF (Sistem e-Faktura, "e-Faktura"), a public platform operated by the Ministry of Finance. Every B2G and B2B invoice must pass through it as structured XML compliant with a national CIUS of the European EN 16931 standard.

Context & legal framework

Serbian e-invoicing is built on the Law on Electronic Invoicing (Zakon o elektronskom fakturisanju, published in the Official Gazette "Službeni glasnik" No. 44/2021 and amended several times). It establishes a mandatory, centralised national system — the SEF (Sistem e-Faktura) — operated by the Ministry of Finance (Ministarstvo finansija); the Tax Administration (Poreska uprava) handles control and VAT recording.

  • Who is in scope? Public-sector entities, VAT payers, and more broadly any operator for its transactions with the State (B2G) and between businesses (B2B).
  • Why? To combat VAT fraud, automate accounting reconciliation, and prepare pre-filled VAT returns from data already held in the system.
  • Model. This is a clearance model: an invoice is not valid unless issued through the SEF, which validates it, timestamps it and delivers it to the buyer.
  • Archiving. E-invoices must be retained for at least 10 years under Serbian accounting and tax rules; the SEF also provides document storage.

As a non-EU country, Serbia is not bound by Directive 2014/55/EU, but it has deliberately aligned its format with the European EN 16931 standard to ease interoperability.

Regulatory timeline

  • May 2021 — Law on Electronic Invoicing adopted (Official Gazette 44/2021).
  • 1 May 2022 — Public sector must be able to receive and store e-invoices (B2G receipt).
  • 1 July 2022 — Public sector must issue e-invoices and electronic VAT recording begins (G2B / B2G issuance).
  • 1 January 2023 — Generalised B2B obligation: every invoice between taxable persons passes through the SEF.
  • 2024-2025 — Successive SEF version upgrades (v3.x), stricter validations, updated internal technical manual and XML examples.
  • November 2024 — Law on electronic delivery notes (e-otpremnice / SEO) adopted, with phased rollout.
  • 1 January 2026 — First e-delivery-note obligations for the public sector and excise goods.
  • 1 April 2026 — 2025-2026 amendments take effect (Official Gazette 109/2025): internal invoices generated within the SEF (self-billing, advances, corrections), mandatory e-invoice for retail sales paid by corporate card, and tighter validation controls.
  • End of 2026 — Several "enhanced B2B" measures (additional fields, electronic storage of all SEF documents, detailed VAT rules) were postponed to end-2026.
  • January 2027 — Rollout of pre-filled VAT returns generated by the SEF (postponed from 2026).

Note: several 2026-2027 dates depend on successive amendments and postponements; verify them on the official portal before any integration project.

Format & technical schema

The mandated format is UBL 2.1 XML constrained by a Serbian CIUS (Core Invoice Usage Specification) of the SRPS EN 16931-1:2019/A2:2020 standard. See our UBL page for the general structure. The document is organised around two namespaces:

  • cbc — Common Basic Components: simple elements (dates, amounts, identifiers).
  • cac — Common Aggregate Components: composite structures (parties, addresses, lines).

The SEF covers several document types: invoice (Invoice), credit note and debit note (CreditNote / DebitNote), advance invoice (avans), and — from April 2026 — internal invoices generated directly inside the platform.

Minimal skeleton of an e-Faktura invoice (illustrative):

<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2"
         xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"
         xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2">
  <cbc:CustomizationID>urn:cen.eu:en16931:2017#compliant#urn:mfin.gov.rs:srbdt:2021</cbc:CustomizationID>
  <cbc:ID>2024-00042</cbc:ID>
  <cbc:IssueDate>2026-06-23</cbc:IssueDate>
  <cbc:DocumentCurrencyCode>RSD</cbc:DocumentCurrencyCode>
  <cac:AccountingSupplierParty>
    <cac:Party>
      <cac:PartyTaxScheme>
        <cbc:CompanyID>RS123456789</cbc:CompanyID>
        <cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme>
      </cac:PartyTaxScheme>
    </cac:Party>
  </cac:AccountingSupplierParty>
  <cac:AccountingCustomerParty>...</cac:AccountingCustomerParty>
  <cac:TaxTotal>
    <cbc:TaxAmount currencyID="RSD">2000.00</cbc:TaxAmount>
  </cac:TaxTotal>
  <cac:LegalMonetaryTotal>
    <cbc:PayableAmount currencyID="RSD">12000.00</cbc:PayableAmount>
  </cac:LegalMonetaryTotal>
  <cac:InvoiceLine>...</cac:InvoiceLine>
</Invoice>

Integration is done either via the SEF portal (manual entry / upload) or via the SEF REST API (system-to-system exchange with an API key). The Ministry publishes an internal technical manual and regularly updated sets of XML examples on efaktura.gov.rs.

Transmission flow

The SEF operates as a centralised clearance system: no B2G/B2B invoice legally exists outside the platform. Typical steps:

  1. Generation — the issuer produces the UBL 2.1 XML (from its ERP, a service provider, or directly in the portal).
  2. Submission — it sends it to the SEF via the API (with its API key) or via the web interface.
  3. Platform validation — the SEF checks UBL syntax, EN 16931 rules, VAT codes and consistency (e.g. the supply date may not be later than the issue date).
  4. Timestamping & delivery — the validated invoice is timestamped and made available to the buyer in its SEF space.
  5. Buyer response — the buyer accepts or rejects the invoice. Statutory deadlines apply for the public sector; for private buyers, a non-response can lead to automatic rejection after a grace period.
  6. VAT recording — the taxable person performs electronic VAT recording in the SEF (the deadline was extended, typically to around the 12th of the month following the tax period).
  7. Forwarding to the CRF — for public-sector transactions, the SEF itself forwards the invoice to the Central Invoice Register (CRF, Centralni registar faktura) run by the Treasury: issuers no longer register separately in the CRF.

Validation & compliance

Compliance rests on three layers of control:

  • UBL 2.1 schema — the XML must be valid against the UBL XSD schema; any malformed element is rejected.
  • EN 16931 business rules (BR-*) — inherited from the European standard via the Serbian CIUS: for example BR-CO-10 (the sum of line net amounts must equal the document net total), the BR-S-* rules for VAT category consistency, or the rules requiring a valid tax identifier for seller and buyer.
  • National SEF rules — Serbia-specific checks added over successive versions: only valid Serbian VAT codes accepted, supply date ≤ issue date, and stricter controls on discounts and detailed transactions (from April 2026).

The Ministry provides an online validation service for UBL 2.1 XML documents on the efaktura.gov.rs portal, letting you test a file before production. The Serbian CIUS (specifikacija upotrebe osnovnog modela fakture) specifies which fields are mandatory, conditional and forbidden relative to the EN 16931 core.

Common pitfalls

  • Confusing "generic" EN 16931 with the Serbian CIUS. An invoice compliant with the EN 16931 core can still fail SEF validation: you must use the Serbian CustomizationID and respect the national rules.
  • Supply date > issue date. Since controls were tightened, the SEF rejects this case — common in poorly configured ERPs.
  • Unrecognised VAT codes. Only category/exemption codes accepted by the SEF pass; a loose ERP mapping causes mass rejections.
  • Forgetting electronic VAT recording. Issuing the invoice is not enough: VAT recording in the SEF is a separate obligation with its own monthly deadline.
  • Double-registering in the CRF. Since the SEF forwards to the CRF itself, re-registering manually creates duplicates; check the status on the SEF side.
  • Private buyer non-response. A missing acceptance/rejection within the deadline can trigger automatic rejection: actively monitor the SEF inbox.
  • Internal invoices outside the SEF (post-April 2026). Self-billing, advances and corrections must now be generated within the platform for SEF users — a breaking point for legacy workflows.
  • Tracking postponements. Several 2026-2027 deadlines (pre-filled VAT, enhanced B2B) have shifted: rely on the official portal rather than old timelines.
  • UBL standard — the base syntax of Serbia's e-Faktura format.
  • Peppol — the reference interoperability network Serbia stays close to via its EN 16931 alignment, without mandating it.
  • EDI / e-invoicing glossary — definitions (CIUS, clearance, EN 16931, VAT).
  • All countries — compare Serbia with other regimes.

Official sources: