Taiwan — e-GUI and the Government Uniform Invoice

In Taiwan, the official invoice is the "Government Uniform Invoice" (統一發票, GUI), a tax document standardised by the Ministry of Finance (財政部). Its electronic version, the e-GUI (電子發票), is issued and transmitted to the MOF e-invoice integration platform, where each invoice carries a serial number allocated by the authority. Introduced from the mid-2000s for B2B/B2G and then broadly extended to B2C retail from 2010-2011, Taiwan's e-GUI is one of the oldest clearance-like systems in Asia; it is paired with the famous bi-monthly unified invoice lottery that encourages consumers to demand their receipt.

Quick facts

Regulator: Ministry of Finance (財政部), via the Fiscal Information Agency and National Taxation Bureaux, operating the e-invoice integration platform (電子發票整合服務平台).
B2G status: The GUI/e-GUI is mandatory for public-sector transactions as for B2B; no separate B2G platform — the channel is the MOF national platform.
B2B status: In force. The GUI is mandatory for every VAT-registered business (營業稅); the e-GUI is very widely used and issuance/numbering remains under tax-authority control. Clearance-like model.
Legal basis: Value-added and Non-value-added Business Tax Act (加值型及非加值型營業稅法); Regulations Governing the Use of Uniform Invoices (統一發票使用辦法); MOF rules and notices governing the e-GUI (電子發票實施作業要點).
Format: MOF national MIG (Message Implementation Guideline) XML — current version 3.2.1 — with B2B / B2C / void / allowance (折讓單) message types. Not UBL/EN 16931, not PEPPOL.
Signature: Transmission authenticated by certificate (MOECA / GCA business and government certificates); authenticity rests on registration with the MOF platform and the allocated invoice number rather than on an EN 16931-style signature.
Identifier: 8-digit Unified Business Number (統一編號, BAN) for businesses; on the consumer side a "carrier" (載具, e.g. mobile barcode card, Citizen Digital Certificate) links the B2C invoice to the buyer.
Portal: MOF e-invoice integration platform (電子發票整合服務平台, einvoice.nat.gov.tw). Transmission via the MOF Turnkey software or accredited value-added service providers.

Regulatory timeline

1950-1951 — creation of the Uniform Invoice (統一發票). Taiwan introduced the paper GUI very early as a standardised, state-numbered tax invoice, paired with a lottery to encourage consumers to demand it.
2000s — first e-GUI pilots. The Ministry of Finance trials the electronic Government Uniform Invoice for B2B/B2G transactions on a standardised XML format.
2006 — legal framework for the e-GUI. Adoption of the rules governing issuance, transmission and retention of the electronic invoice (電子發票實施作業要點).
2010-2011 — B2C rollout and integration platform. The MOF deploys the national integration platform (電子發票整合服務平台) and extends the e-GUI to retail, introducing the "carrier" concept (載具) to dematerialise the consumer receipt.
2013-2014 — retail ramp-up. Retail chains, convenience stores (7-Eleven, FamilyMart) and e-commerce migrate heavily to the B2C e-GUI; the lottery becomes checkable and payable electronically.
2010s-2020s — MIG format iterations. The MOF evolves the exchange specification (Message Implementation Guideline) up to version 3.2.1, the current reference, refining the message types (B2B, B2C, void, allowance).
2020-2025 — consolidation. The e-GUI becomes the default issuance mode for a large share of the economy; a common carrier (共通性載具), a mobile app and automatic lottery-prize transfer strengthen adoption. (Recent calendar specifics: to confirm with the MOF.)

Technical schema

Taiwan uses neither a European semantic format (UBL, CII, EN 16931) nor the PEPPOL network. The e-GUI relies on a national XML specification owned by the Ministry of Finance:

Format: MOF MIG (Message Implementation Guideline) XML, current version 3.2.1, with distinct messages: B2B (business-to-business), B2C (business-to-consumer), void invoice (作廢) and allowance / credit note (折讓單).
Business identifier: 8-digit Unified Business Number (統一編號, BAN), used as seller and buyer for B2B.
Invoice number: a structured unified invoice number (two track letters + 8 digits, e.g. AB-12345678) allocated in ranges under tax-authority control; it is this number that enters the lottery draw.
Carrier (載具): on the B2C side, an invoice can be attached to a dematerialised "carrier" — mobile barcode card (手機條碼載具), Citizen Digital Certificate (自然人憑證), membership card — instead of a paper receipt.
Authenticity: ensured by registration with the MOF platform and a transmission certificate (MOECA for businesses, GCA for government), not by an EN 16931-style issuer signature.

Schematic e-GUI header (simplified, non-normative XML):

<Invoice>
  <InvoiceNumber>AB12345678</InvoiceNumber>
  <InvoiceDate>20260516</InvoiceDate>
  <Seller><Identifier>12345678</Identifier><Name>示範科技股份有限公司</Name></Seller>
  <Buyer><Identifier>87654321</Identifier></Buyer>
  <TaxType>1</TaxType>
  <SalesAmount>10000</SalesAmount>
  <TaxAmount>500</TaxAmount>
  <TotalAmount>10500</TotalAmount>
</Invoice>

The real schema is the MOF-standardised MIG 3.2.1; this block only illustrates the load-bearing fields (standard VAT rate 5%).

Submission flow

Taiwan's model is tax-authority-supervised issuance (often described as "clearance" or "clearance-like" by vendors), centred on the MOF integration platform and distinct from the four-corner PEPPOL model:

1. Number allocation. The tax authority allocates businesses ranges of unified invoice numbers (two track letters + 8 digits) per bi-monthly period; no valid invoice can be issued outside those ranges.
2. Issuance. The seller generates the e-GUI in its ERP / POS system in MIG 3.2.1 format and issues it — for consumer B2C, by printing a lightweight receipt or attaching it to a carrier (載具).
3. Transmission to the platform. Invoices (B2B and B2C) are uploaded to the MOF integration platform (電子發票整合服務平台) via the ministry's Turnkey software or an accredited value-added provider, under certificate (MOECA/GCA), within a regulated deadline.
4. Reconciliation, lottery and deduction. The MOF stores and reconciles invoices; B2C numbers enter the bi-monthly unified invoice lottery draw (統一發票兌獎), and VAT-registered buyers retrieve their B2B e-GUIs for input-VAT deduction.

Unlike an open interoperability network, there is no mandatory third-party Access Point in the PEPPOL sense: the MOF platform is the central pass-through, businesses connecting via Turnkey or an accredited operator.

Validation

Verify the format, status and authenticity of an e-GUI through the official sources:

Note: the MIG specification (including version 3.2.1) and Turnkey guides are published on einvoice.nat.gov.tw; registration and lottery-draw rules are specific to the MOF. Confirm case by case for the most recent version and calendar details.

Common pitfalls

Assuming a UBL/PEPPOL-style format. Taiwan is neither on PEPPOL nor on EN 16931: the format is the MOF national MIG XML (3.2.1). A European e-invoicing connector does not plug in as-is.
Forgetting number allocation. Unified invoice numbers are allocated in bi-monthly ranges under tax-authority control. Issuing outside a range, or exhausting a range without renewing it, blocks invoicing.
Neglecting the carrier (載具) in B2C. For retail, correctly attaching the invoice to a carrier (mobile barcode, Citizen Digital Certificate) is what dematerialises the receipt and makes the customer eligible for the lottery.
Underestimating the unified invoice lottery. The bi-monthly draw (統一發票兌獎) is not a gimmick: it is the incentive that pushes consumers to demand invoices and so secures the VAT base. Ignoring it misreads the whole system.
Confusing Turnkey with a third-party operator. The MOF provides the Turnkey software, but many businesses use an accredited value-added provider; the choice affects integration, certificates and transmission deadlines.
Assuming an EN 16931-style issuer signature. Authenticity comes from registration with the MOF platform and the transmission certificate (MOECA/GCA), not from a vendor electronic seal.

Foundations

Standards

Flagship messages

Tools