Taiwan e‑invoicing (eGUI) explained: what businesses need to know

TL;DR summary

• Taiwan e‑invoicing (eGUI) is mandatory for most B2B and B2C transactions and is a core component of the country’s tax digitalisation strategy.
• All e‑invoices must follow the MIG 4.0 XML standard, be digitally signed, AES‑encrypted and transmitted to the Ministry of Finance’s e‑invoice platform within strict deadlines
• Non‑compliance can trigger fines per invoice, plus audit exposure and potential disruption to customer and partner relationships
• To achieve compliance, businesses must map in‑scope flows, connect their systems to the MoF platform (directly or via a certified provider), and put in place robust monitoring and archiving
• Outsourcing to a fully managed global e‑invoicing provider can significantly reduce operational risk and ongoing maintenance effort

What is Taiwan e‑invoicing (eGUI)? An overview

Taiwan e‑invoicing (eGUI) is the country’s electronic government uniform invoice system. Instead of paper or PDF invoices, taxable transactions are captured in a structured XML format and reported electronically to the Ministry of Finance (MoF).

The eGUI model applies to both business‑to‑business (B2B) and business‑to‑consumer (B2C) transactions. Every e‑invoice must be transmitted to the MoF’s e‑invoice platform, operated by the Fiscal Information Agency (FIA). To do this, taxpayers can either:

• Use the official Turnkey software provided by the MoF, or
• Connect via a certified value‑added centre (VAC)

In both cases, e‑invoices must comply with the MIG 4.0 implementation guideline, include a valid digital signature and be AES‑encrypted in transit.

For B2C transactions, Taiwan goes a step further: each consumer invoice includes an encrypted QR code and lottery information, turning the fiscal receipt into a customer engagement tool. Cross‑border digital service providers selling to Taiwanese customers are also in scope, which means non‑resident businesses need to comply with the same core eGUI rules as domestic taxpayers.

Taiwan’s e‑invoicing journey: a timeline

Taiwan has moved from voluntary pilots to a near‑universal e‑invoicing requirement over several years.

Key milestones:

• 1 January 2021 – eGUI becomes mandatory for all business tax‑registered entities, covering both B2B and B2C transactions
• 1 January 2024 – MIG 4.0 is established as the standard implementation guideline for Taiwan e‑invoicing
• 7 August 2024 – Amendments to the Business Tax Act strengthen procedures for e‑invoicing and clarify penalties for non‑compliance
• 31 December 2025 – End of the transition period for legacy MIG 3.1 / 3.2 formats. From this point, MIG 4.0 is expected to be the default

For ongoing updates on upcoming changes and detailed technical specifications, it is best practice to consult Taiwan’s official guidance and stay aligned with your implementation partners.

How Taiwan’s e‑invoicing regulations affect your business

The exact impact of Taiwan e‑invoicing rules depends on your role and footprint, but in most cases you can expect changes in three areas:

1. Invoicing processes
   • Replacing paper/PDF invoices with eGUI‑compliant XML messages
   • Ensuring every invoice issued or received fits the required data structure and content fields

System integration

• Connecting your ERP, billing, and POS systems to the MoF e‑invoice platform (directly or via a VAC/managed provider)
• Handling digital signatures, encryption and acknowledgements within normal business workflows

Compliance and audit readiness

• Designing processes that respect issuance and transmission deadlines
• Implementing secure, searchable archiving for the required retention period so documents can be produced during audits

For businesses entering Taiwan for the first time, these requirements should be factored in early during market entry planning rather than treated as a late‑stage technical add‑on.

Who is in scope for Taiwan’s e‑invoicing?

In practice, Taiwan’s e‑invoicing rules affect a wide range of organisations:

• Domestic suppliers issuing B2B and B2C invoices for taxable supplies in Taiwan
• Foreign digital service providers selling to Taiwanese customers, who need to align with eGUI requirements despite not being established locally
• Buyers that receive B2B and B2C invoices, especially where QR codes, lottery elements and specific content rules must be respected for input VAT and accounting purposes
• Self‑billing scenarios, where buyers issue invoices on behalf of suppliers using the supplier’s tax ID and allocated eGUI number ranges, under formal agreements

If your organisation touches any of these flows, you will likely need to review and adjust your invoicing and reporting landscape.

What are the penalties for non‑compliance with Taiwan’s e‑invoicing rules?

The MoF can impose administrative fines per violation for a range of issues, including:

• Late or missing transmission of e‑invoices to the e‑invoice platform
• Incorrect, incomplete or inconsistent invoice data
• Missing digital signatures or encryption, or invalid eGUI numbering

Depending on the nature and frequency of the breach, penalties can reach into the thousands of New Taiwan Dollars (NT$) per invoice, and can escalate for repeated violations. Beyond direct fines, non‑compliance can also lead to:

• Audit risk and increased scrutiny from tax authorities
• Operational disruption, as invalid invoices may need to be cancelled and reissued
• Strained relationships with customers, partners, and platforms that rely on timely, valid e‑invoices to run their own processes

Combining robust controls with proactive monitoring is therefore essential.

How to achieve compliance in Taiwan

Achieving compliance in Taiwan is an ongoing process. To gain compliance you should:

Map your in‑scope flows

• Identify all B2B, B2C, and cross‑border digital transactions that fall under the eGUI regime
• Clarify which business units, systems, and entities are involved

Review data and master‑data readiness

• Check that your ERP and billing systems can produce the fields required by MIG 4.0
• Confirm that tax IDs, product codes, and customer references are clean and consistent

Choose your connection model

• Decide whether to implement the MoF Turnkey solution, connect directly to a VAC, or work with a managed e‑invoicing provider that already has certified connectivity

Implement, test, and go live

• Build the necessary integrations and transformations to generate eGUI‑compliant XML
• Test end‑to‑end flows, including digital signatures, encryption, acknowledgements, and error handling

Set up monitoring and archiving

• Put in place dashboards and alerting for failed or delayed transmissions
• Ensure compliant archiving of e‑invoices for at least the mandatory retention period, in a format that can be retrieved for inspections

Your two compliance options compared

Once you understand what needs to be done, the key decision is how to manage e-invoicing in Taiwan. There are two main paths businesses can take here – either handle it in‑house or enlist the help of a fully managed provider.

For organisations already dealing with multiple e‑invoicing mandates worldwide, the managed route is often preferable, as it centralises complexity and frees internal teams to focus on core processes.

How ecosio helps with Taiwan e-invoicing (eGUI)

With ecosio’s Global E‑invoicing Compliance solution, businesses can integrate Taiwan e‑invoicing into a unified, managed framework rather than building a standalone local fix.

In particular, ecosio can support you by:

• Managing MIG 4.0 transformation from your existing ERP or billing data into eGUI‑compliant XML
• Handling digital signatures, AES encryption and secure submission to the MoF e‑invoice platform via certified connectivity
• Monitoring e‑invoice flows end to end, with alerting and error handling for failed or delayed messages
• Taking care of regulatory and technical updates, so changes in Taiwan’s rules are reflected in your processes without repeated internal projects
• Providing centralised visibility into your Taiwanese e‑invoicing flows through a single interface, alongside other countries’ mandates

Ready to become compliant in Taiwan?

Taiwan’s e‑invoicing framework is mature, but with the right approach it doesn’t have to be complex.

If you’d like a concise checklist for Taiwan e‑invoicing readiness or help evaluating in‑house versus managed models for your organisation, please reach out to our team to discuss your specific situation and next steps

Stay up-to-date

Make sure you never miss important e-invoicing updates again. With ecosio there are multiple ways to stay on top of e-invoicing developments…

• E-invoicing updates newsletter – Subscribe to our email newsletter and for news and information on e-invoicing updates, plus tips, tools and other helpful assets
• Taiwan compliance overview page – A comprehensive breakdown of current regulations and requirements
• E-invoicing deadlines calendar – Never miss another mandate or regulation change with our detailed e-invoicing deadline tracker

E-invoicing in Taiwan FAQs

Which formats are accepted for Taiwan e‑invoicing?

The current standard is MIG 4.0 XML. Earlier versions (such as MIG 3.1/3.2) may only be accepted during a defined transition period, after which MIG 4.0 is expected to be mandatory.

What are the transmission deadlines?

Deadlines can differ depending on the transaction type, but conceptually you should expect tight windows between invoice issuance and reporting to the MoF. Your integration must be designed so that invoices reach the e‑invoice platform within these deadlines, even during peak volumes.

Are digital signatures and encryption mandatory?

Yes. eGUI invoices must be digitally signed and AES‑encrypted. For B2C invoices, an encrypted QR code containing lottery information is also required.

How are eGUI numbers allocated?

The MoF allocates bi‑monthly e‑invoice number ranges. Taxpayers are responsible for requesting new ranges before their current pool is exhausted and for using numbers in accordance with the rules.

Is self‑billing (buyer‑created invoices) allowed?

Self‑billing is possible under specific conditions. Buyers can issue eGUI invoices on behalf of suppliers using the supplier’s tax ID and number range, as long as there is a formal agreement and all technical and timing requirements are met.