E-Invoicing in Portugal:
B2G Mandate, ATCUD, QR code, QES & certified solutions

Last update: 2026, October 20

Summary

Portugal has required large suppliers to issue electronic invoices to public administrations since 2021. Other invoicing requirements apply across the country, including certified invoicing software, ATCUD identifiers and QR codes, while the extension of B2G e-invoicing to SMEs and the end of the temporary acceptance of simple PDF invoices continue to be postponed.

B2G Transactions

Mandatory e-invoicing acceptance, and mandatory issuance for large suppliers

B2G e-invoicing is mandatory for large suppliers, and while all Portuguese public administrations are theoretically required to accept electronic invoices in CIUS-PT XML format, this is not always the case in practice.

There is no single platform, so suppliers and public recipients must agree on a delivery method.

B2B Transactions

No e-invoicing obligation

No e-invoicing obligation applies to business-to-business transactions in Portugal, but e-invoicing is possible upon mutual agreement between trading partners.

Multiple requirements apply countrywide: certified invoicing solution, ATCUD unique identifier, SAF-T reporting, QR codes, and eventually Qualified Electronic Signatures (QES).

B2C Transactions

No e-invoicing obligation

No e-invoicing obligation applies to business-to-consumer transactions in Portugal.

Multiple requirements apply countrywide: certified invoicing solution, ATCUD unique identifier, SAF-T reporting, QR codes, and eventually Qualified Electronic Signatures (QES).

What the Law Says

B2G E-Invoicing mandate

Portugal has been working towards mandatory B2G e-invoicing for several years, but successive postponements mean that, for now, the obligation applies only to large suppliers of public administrations.

The mandate is coordinated by eSPap, the Portuguese public administration’s shared services entity, which also provides a platform called FE-AP (Fatura Eletrónica na Administração Pública).

Public entities can use FE-AP to receive electronic invoices, but not all of them are required to use it. eSPap maintains a list of public entities connected to the platform [↗︎]. For recipients that are not available through FE-AP, suppliers must agree on another delivery method with the public entity, such as EDI, manual upload or email.

B2G e-invoices must be issued in CIUS-PT format, the Portuguese national specification of the European Norm (EN) 16931. They must also contain a unique document identifier called the ATCUD.

The mandate is currently scheduled to extend to small and medium-sized suppliers on January 1, 2027, following several postponements. However, the government has proposed yet another extension in its 2027 State Budget proposal [↗︎], which would postpone their entry into scope until January 1, 2028 if adopted.

Invoices must generally be archived for ten years.

Other Invoicing Flows (B2B, B2C, Non-Electronic B2G)

E-invoicing is voluntary for companies not in scope of the B2G e-invoicing mandate and for B2B transactions. Portugal does not have a B2B or a B2C e-invoicing mandate.

Where e-invoicing is not mandatory, businesses can issue and exchange invoices in different formats, with electronic invoices subject to acceptance by the recipient:

Paper-based invoices
PDF invoices
Electronic invoices, exchanged for example via EDI

Most Portuguese businesses must use certified invoicing software. This requirement applies if they meet any of the conditions set out in Decree-Law No. 28/2019 [↗︎].

B2B invoices must contain a unique document identifier called the ATCUD. Invoices issued using certified invoicing software and delivered in PDF or paper form must include a QR code.

PDF invoices will also eventually be required to contain a Qualified Electronic Signature (QES) or Seal. The current application date is January 1, 2027, but the government has proposed postponing it yet again, until January 1, 2028, in its 2027 State Budget proposal [↗︎].

Finally, businesses must also report invoice data to the Portuguese tax authority, either through a web service, a SAF-T (PT)-based file or manual entry on the tax portal, but this reporting obligation will not be covered in detail on this page.

Invoices must generally be archived for ten years.

Timeline

E-Invoicing accepted by all public entities

All central & local administrations in Portugal must be able to receive electronic invoices.

B2G e-invoicing mandatory for large suppliers

Large suppliers must send electronic invoices to Portuguese public administrations in CIUS-PT format

Mandatory QR codes on PDF & paper invoices

Most businesses must use a certified invoicing solution, and their paper & PDF invoices must include a QR code

B2G e-invoicing mandatory for SMEs

Proposed date for the B2G e-invoicing mandate to take effect for SMEs

Mandatory QES for PDF invoices

Proposed date for B2B PDF invoices to include a Qualified Electronic Signature or Seal, in order to remain allowed.

2019-2020

2021

2022

Jan 1, 2028 ?

Latest E-Invoicing News in Portugal

Photo of the European Parliament, gathered within the European Commission in Brussels, capital of Belgium

European Commission calls for public input to shape the future of EU e-invoicing

A “Reality Check” event and a public consultation launched by the European Commission aim to shape EU e-invoicing by gathering feedback.

Set of flags from around the world waving in the wind

EN 16931 update: the next step in e-invoicing is on its way

With the EU shifting from public e-invoicing mandates to full B2B, the EN 16931-1 update will arrive mid-2026 to raise compliance standards.

Photo of Belem tower at sunset, in Lisbon, capital of Portugal

Another delay for mandatory e-signature on PDFs in Portugal

PDF invoices without an electronic signature will remain allowed in Portugal for one more year, until January 1, 2027.

See all recent news

Technical Details - B2G E-Invoicing Mandate

B2G e-invoicing in CIUS-PT XML format is mandatory for large suppliers in Portugal and voluntary for other suppliers. All Portuguese public administrations are theoretically able to receive electronic invoices, but different delivery methods are in use.

Invoice format & content

Most Portuguese businesses must use certified invoicing software to issue their electronic invoices, as described further below.

The content of structured B2G e-invoices in Portugal is defined by the CIUS-PT invoice format, the Portuguese specification of the European Norm (EN) 16931. It sets out how the European standard is applied in Portugal, including local requirements, and can be represented in XML using the UBL or CII syntaxes.

The CIUS-PT technical specifications [↗︎] are published and maintained by eSPap, the Portuguese public administration’s shared services entity.

B2G invoices (electronic or not) in Portugal must also include an ATCUD unique identifier, as described further below.

Invoice delivery

The central platform FE-AP [↗︎] (Fatura Eletrónica na Administração Pública) was developed by eSPap (Entidade de Serviços Partilhados da Administração Pública). Public administrations across the country can use it to receive electronic invoices.

Suppliers wishing to join FE-AP must complete an onboarding process that may include a questionnaire, configuration and testing. Further details are available in the FE-AP technical documentation [↗︎].

Alternatively, small suppliers issuing fewer than 250 documents per year can use the FE-AP Microportal [↗︎] to transmit invoices manually to public entities registered on the platform.

However, public administrations are not required to use FE-AP, resulting in a very complex B2G e-invoicing landscape. Each public entity may have different transmission requirements.

Suppliers can start by checking the list of public entities using FE-AP [↗︎] maintained by eSPap. If the recipient is not listed, the supplier should contact its public customer to confirm how electronic invoices must be transmitted.

The following delivery methods are used in Portugal:

FE-AP central platform: Suppliers can transmit CIUS-PT e-invoices through web services or via AS2 using a technology provider.
Third-party portals: Many public entities use portals operated by service providers. These portals may offer several transmission methods, from manual submission to EDI, but are often available at a cost to the supplier.
Direct EDI connection: Some public entities may ask suppliers to transmit e-invoices through a direct connection configured between the two parties.
Email: Depending on the recipient’s requirements, suppliers may also be asked to send their CIUS-PT e-invoices by email.

Technical Details - Other Invoicing Flows (B2B, B2C, Non-Electronic B2G)

Invoices in Portugal require an ATCUD unique identifier, and most businesses, besides very small ones, must use a certified service provider. PDF or paper invoices issued through certified software must contain a QR code.

ATCUD unique identifier

Invoices in Portugal must include an ATCUD, a unique identifier (Código Único de Documento – CUD) that helps the Portuguese Tax and Customs Authority (Autoridade Tributária – AT) identify and track each document, as detailed in AT’s official FAQ [↗︎].

To create it, the supplier first registers its invoice series with the Portuguese Tax and Customs Authority (AT), which assigns a validation code to that series. This code is then combined with the invoice’s sequential number to form the ATCUD.

Certified invoicing software

Most Portuguese businesses must use certified invoicing software. This requirement applies if they meet any of the following conditions, as set out in Decree-Law No. 28/2019 [↗︎].

Their turnover exceeded €50,000 in the previous calendar year.
They are required to keep organised accounting records, or have chosen to do so.
They use invoicing software, even if they do not meet either of the other conditions. In this case, the software must be certified.

The tax authority (AT) maintains a list of certified invoicing software [↗︎].

QR code for PDF & paper invoices

Invoices issued in PDF or paper format using certified invoicing software must include a QR code, whether they are sent to a public entity, a business or a final consumer.

The QR code contains key invoice data, including the issuer’s tax identification number, the invoice date and number, the ATCUD, and the invoice and VAT amounts. Further information is available in the official QR code FAQ [↗︎].

Recipients can scan the QR code to capture the invoice data more easily. For example, consumers can use the Portuguese tax authority’s e-Fatura app to register invoices and manage their tax-deductible expenses.

Qualified Electronic Signature (QES)

Portugal currently allows businesses to issue and exchange simple PDF invoices until at least December 31, 2026, and likely until December 31, 2027, as proposed by the government in its 2027 State Budget proposal [↗︎].

After this temporary provision expires, businesses will need to ensure the authenticity of the origin and the integrity of the content of their PDF invoices.

One way to do so is to apply a Qualified Electronic Signature (QES) or a Qualified Electronic Seal. Both rely on a qualified certificate and help identify the signer or issuer and detect changes to the document.

The QES can be applied by an authorised representative of the issuing company, either directly or through the certified invoicing software it uses.

The Invoicing Hub Word

Portugal

Portugal’s B2G e-invoicing mandate was intended to provide a straightforward way for suppliers to send invoices electronically to public administrations.

In practice, its implementation has faced numerous complications and delays, partly due to Covid and partly to the slow adoption of e-invoicing by public entities and businesses. Repeated postponements for SMEs have also made it harder for companies to plan ahead.

The situation is nevertheless relatively clear when it comes to B2G invoice formats, with CIUS-PT as the structured format and PDF still accepted for many suppliers not yet within the scope of the mandate.

Delivery of invoices to public customers, however, is much more complex. Public entities are not required to use the FE-AP central platform and can choose other solutions, leaving suppliers to navigate third-party portals, direct EDI connections and, in some cases, even email.

Combined with the requirements for certified invoicing software, QR codes, the ATCUD and SAF-T transmissions (not described on this page), this creates a landscape that can be difficult for companies to navigate. Working with an experienced service provider can help businesses manage these different requirements and delivery channels.

With ViDA on the horizon, Portugal has an opportunity to bring greater clarity and consistency to its e-invoicing framework. A simpler approach would help businesses move beyond compliance and make better use of the benefits of e-invoicing, particularly automation and more efficient invoice processing.