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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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South Korea — NTS, e-Tax Invoice and Cash Receipt

South Korea has operated an e-Tax Invoice (세금계산서) mandate since 2011, driven by the NTS (National Tax Service). The system, one of the most mature in the world, has been complemented with the Cash Receipt System since 2005, and requires transmission to NTS via Hometax within 24 hours or face penalties.

Regulatory timeline

  • 1 January 2005 — Cash Receipt System launched. Voluntary mechanism for automated registration of B2C cash payments (transport card, NTS smartphone, phone number) — becomes mandatory in certain sectors in 2010.
  • 27 December 2009 — Amended VAT Law (부가가치세법). Introduces the e-Tax Invoice obligation for corporations, effective 2011.
  • 1 January 2011 — e-Tax Invoice go-live for corporations. Every commercial corporation must issue Tax Invoices in electronic format via Hometax or ASP.
  • 1 January 2012 — Extension to individual proprietors at the KRW 1 bn threshold. First threshold drop for individual entrepreneurs (turnover > KRW 1 billion).
  • 2014-2024 — Progressive threshold lowering. KRW 300 M in 2018, KRW 200 M in 2022, KRW 100 M in 2023, KRW 80 M since 1 July 2024.
  • 1 July 2014 — e-Tax Invoice extension to Calculation Sheet (계산서). For VAT-exempt operations (medical, education, etc.), a separate document (간이세금계산서) is also digitised.
  • 2022-2023 — NTS Open API modernisation. Overhaul of Hometax interfaces with REST + JSON APIs alongside the historical SOAP/XML, for cloud ERPs.
  • 2025-2026 — NTS Standard 2025 programme. Strengthens B2B interoperability with XSD updates and a focus on automated Tax Invoice matching on the NTS side for VAT controls.

Technical schema

The format is NTS XML based on KEC (Korea Electronic Commerce Association) schemas. Features:

  • Namespace: http://www.kec.or.kr/standard/Tax/TaxInvoiceSchemaModule/1.
  • Document type: TaxInvoice (세금계산서) for VAT-taxable sales, Calculation Sheet (계산서) for exempt sales.
  • TypeCode: 0101 (standard B2B sale), 0102 (credit note), 0201 (cash receipt), etc.
  • Business Registration Number: 10 digits in NNN-NN-NNNNN format, validated by the official NTS formula (check digit).
  • BusinessClassCode: Statistics Korea (KSIC — 한국표준산업분류) activity code, 5 digits.
  • NPKI signature: XMLDSig block with embedded NPKI (X.509) certificate.

Minimal example of a B2B e-Tax Invoice:

xmletax-invoice-kr-nts.xml
<?xml version="1.0" encoding="UTF-8"?>
<TaxInvoice xmlns="http://www.kec.or.kr/standard/Tax/TaxInvoiceSchemaModule/1">
  <ExchangedDocument>
    <ID>20260516-91038271-12345</ID>
    <IssueDateTime>20260516103000</IssueDateTime>
    <TypeCode>0101</TypeCode>
  </ExchangedDocument>
  <TaxInvoiceTradeSettlement>
    <InvoicerParty>
      <ID>123-45-67890</ID>
      <NameText>Ediverse Demo Korea Co. Ltd.</NameText>
      <SpecifiedOrganization>
        <RepresentativePersonName>HONG GIL DONG</RepresentativePersonName>
        <BusinessTypeCode>S</BusinessTypeCode>
        <BusinessClassCode>62010</BusinessClassCode>
      </SpecifiedOrganization>
    </InvoicerParty>
    <InvoiceeParty>
      <ID>987-65-43210</ID>
      <NameText>Customer Demo Korea Co. Ltd.</NameText>
    </InvoiceeParty>
    <SpecifiedMonetarySummation>
      <ChargeTotalAmount>10000000</ChargeTotalAmount>
      <TaxTotalAmount>1000000</TaxTotalAmount>
      <GrandTotalAmount>11000000</GrandTotalAmount>
    </SpecifiedMonetarySummation>
  </TaxInvoiceTradeSettlement>
</TaxInvoice>

Submission flow

The seller has three channels to transmit to the NTS:

  • Hometax direct: free NTS web portal for low volume (manual input or XML upload).
  • Certified ASP: SaaS vendor acting as NTS Service Provider (Bill36524, Smart Bill, Saerom, etc.). The ASP signs, transmits to NTS and notifies the buyer.
  • e-Tax Invoice direct API: direct integration between the seller's ERP and NTS infrastructure, for very large enterprises.
textnts-etax-flow.txt
┌──────────────┐    ┌──────────────────┐    ┌──────────────┐
│ KR supplier  │───>│ Hometax / NTS    │───>│ KR customer  │
│ (ERP, XML)   │    │ ASP/SaaS         │    │ (ERP, XML)   │
│ + NPKI sig.  │    │ (transmission    │    │ + receipt    │
│              │    │ within 24h)      │    │ acknowledge  │
└──────────────┘    └────────┬─────────┘    └──────────────┘
                             │
                             ▼
                  ┌─────────────────────┐
                  │ NTS Hometax stores  │  ← 1%-2% penalty
                  │ and indexes for VAT │     if > 24h transmit
                  └─────────────────────┘

The deadline for NTS transmission is 24 hours after issuance. A transmission between 24h and 25 days triggers a 1 % penalty on the invoice amount; beyond, 2 %. This is a Korean specificity: the mandate is not a pre-issuance clearance but a very strict post-issuance reporting obligation.

Validation

  • Hometax: hometax.go.kr — NTS portal for issuance, lookup and VAT filing.
  • NTS — National Tax Service: nts.go.kr/english — English-language section of the regulator.
  • KEC — Korea Electronic Commerce Association — editor of standard XML schemas and code lists.
  • KISA — Korea Internet & Security Agency: kisa.or.kr — root NPKI authority.

Common pitfalls

  1. 24h deadline vs VAT payment. NTS computes the bimonthly VAT based on Tax Invoices transmitted on time. A late transmission can shift the buyer's VAT deduction by a month. Monitor transmission age on critical flows.
  2. NPKI vs Banking Certificate. The NPKI certificate is distinct from the banking certificate (NPKI vs Banking PKI) — both are used for different purposes. The NPKI Tax Invoice signature is irrelevant for bank authentication and vice versa.
  3. KSIC code mandatory and precise. The BusinessClassCode (KSIC 5-digit) must match the activity declared to NTS at the commercial registry. A wrong code triggers a flag on the taxpayer profile and complicates audits.
  4. Cash Receipt mandatory B2C in sensitive sectors. Some sectors (health, education, real estate) have lower thresholds (KRW 100,000) and mandatorily require the Cash Receipt System even without customer request. Fines for non-issuance reach 20 % of the amount.
  5. Issuance date vs Supply date. The IssueDateTime must reflect the effective supply date of the good/service, not the XML generation date. A mismatch is sanctioned if the invoice is transmitted in the wrong bimonthly VAT cycle.