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🇷🇸 Serbia - Invoicing Specifications (SEF / E-Faktura)

Status: 🔴 Mandatory Clearance (B2B / B2G) Authority: Ministry of Finance (Poreska uprava) Platform: SEF (Sistem E-Faktura)

1. Context & Roadmap

Serbia operates a centralized Clearance system. The SEF platform is the mandatory hub for all invoice exchange. Crucial Rule: Invoices not issued via SEF are legally void.

DateScopeObligation
ActiveB2GMandatory since May 2022.
ActiveB2BMandatory since Jan 2023.
Jan 1, 2026Logisticse-Delivery Note (e-Otpremnica) mandatory for B2G & Excise goods.
Apr 1, 2026InternalInternal invoices (e.g., self-use) must be reported to SEF.
Jan 1, 2027VATPre-filled VAT return implementation.

2. Technical Workflow (Clearance Hub)

The SEF acts as a "hub". You send the invoice to SEF; SEF validates it and makes it available to the buyer.

sequenceDiagram
    participant S as Invoicerr
    participant SEF as Sistem E-Faktura
    participant B as Buyer
    
    Note over S: 1. Authentication
    S->>S: API Key (Derived from Qualified Cert)
    
    Note over S: 2. Submission
    S->>S: Generate XML (UBL 2.1 / SRBEFN)
    S->>SEF: POST /sales-invoice
    SEF-->>S: 200 OK + InvoiceId (Processing)
    
    Note over B: 3. Acceptance Logic
    SEF->>B: Notify New Invoice
    
    alt Buyer Action (B2B)
        B->>SEF: Accept / Reject
    else Buyer Inaction (15+5 Days)
        SEF->>S: Auto-Reject (B2B) / Auto-Accept (B2G)
    end

🧱 Key Components

  1. SRBEFN (CIUS): The Serbian implementation of UBL 2.1.
  2. JBKJS (Public User Number): A unique ID for public entities. Mandatory for B2G.
  3. API Key: Generated via the SEF Portal using a Qualified Electronic Certificate (e.g., Halcom/MUP).
  4. Auto-Rejection (B2B): If a B2B buyer ignores the invoice for 20 days (15+5), it is automatically REJECTED.
  5. Auto-Acceptance (B2G): If a B2G buyer ignores the invoice for 15 days, it is automatically ACCEPTED.

3. Data Standards & Requirements

A. Format: UBL 2.1 (SRBEFN)

  • Structure: Standard UBL.
  • CustomizationID: Must be urn:mfin.gov.rs:srbefn:2021.
  • Delivery Date: ActualDeliveryDate is mandatory and cannot be in the future.

B. Tax Categories

  • S (Standard 20%).
  • AE (Reverse Charge) - Must include exemption reason code.
  • Z (Zero-rated / Export).
  • OE (Out of Scope).

4. Transmission & Acceptance

  • B2B Logic: The system is "active". The buyer must accept the invoice on the portal for it to be fully valid for VAT deduction. If they sleep, the invoice dies (Rejected).
  • B2G Logic: Silence implies consent (Accepted).

5. Implementation Checklist

  • API Connector: Build the REST client for efaktura.mfin.gov.rs.
  • JBKJS Field: Add a specific field for Public Sector clients to input their JBKJS number.
  • Status Loop: Implement a robust status checker. You need to know if the invoice was "Accepted", "Rejected", or "Auto-Rejected".
  • Tax Mapping: Map internal tax rates to SRBEFN codes (S, AE, Z, etc.).
  • Delivery Note (Future): Prepare for DespatchAdvice XML for 2026 mandates.

6. Resources