Portugal is not a peripheral compliance topic for the CIO of a European mid-market company with operations in Southern Europe. The country has been engaged since 2008 in one of the continent’s most advanced fiscal digitisation programmes — one frequently cited as a reference model by administrations designing their own audit systems. Yet its 2026-2027 regulatory calendar remains largely unknown outside the teams responsible for Iberian subsidiaries.
This guide covers the four obligations that define digital tax compliance in Portugal, their actual implementation status, and what your ERP needs to deliver before the next deadlines.
Portugal: A European Pioneer in Digital Tax Compliance
The Autoridade Tributária e Aduaneira (AT), Portugal’s tax and customs authority, introduced SAF-T (Standard Audit File for Tax) in 2008 for large companies, then progressively extended it to SMEs. This standardised XML file, known as SAF-T (PT), enables the AT to receive billing and accounting data in a unified format that can be processed by automated analysis tools.
This head start explains the maturity of Portugal’s framework. While other EU member states are still rolling out mandatory e-invoicing platforms, Portugal has required — for over fifteen years — that every VAT-registered business use AT-certified billing software. Certification is not an optional audit: non-certified software cannot legally be used to issue invoices in Portugal.
Why is Portugal accelerating now? Two reasons converge. First, the transposition of the European e-invoicing directive (EN 16931) and commitments made under Portugal’s Recovery and Resilience Plan. Second, the fight against VAT fraud in a country where the shadow economy remains significant and the AT is working to close the gap between collected VAT and theoretical VAT (the “tax gap”).
SAF-T Portugal: Two File Types, Two Timelines
Monthly SAF-T Billing: In Force Since January 2023
SAF-T billing (the invoicing file) is the most operationally demanding part of the framework. All VAT-registered businesses in Portugal must submit to the AT an SAF-T file containing their previous month’s billing data. The deadline is the 5th of the following month (Faturado, Invoicing Deadlines 2026).
This obligation has been in force since January 2023. It also applies to non-resident companies that hold a Portuguese VAT number. Even months with no invoicing are covered: the AT requires a nil declaration, also due before the 5th of the following month.
The SAF-T billing file includes master data (customers, products, VAT table) and transactions (invoices, credit notes, receipts). The AT provides a validation tool (SVAT) that companies can use to check their file before submission.
What this means for your ERP: the invoicing module must be able to generate a SAF-T (PT) file at version 1.04 or higher within the required deadlines. This capability is native in AT-certified ERPs and in the Portuguese localisations of major platforms. For generic ERPs deployed without a Portuguese localisation, the absence of an SAF-T module is an immediate compliance problem — not a functional gap to address later.
SAF-T Accounting: Heading Towards 2028-2029
SAF-T accounting, distinct from SAF-T billing, covers general ledger data. Its introduction has been delayed several times.
The 2026 Finance Act (Lei n.º 73-A/2025 of 30 December 2025) had set a first obligation for fiscal year 2027, with the first submission due in 2028. The 2027 budget proposal, submitted in October 2026 and scheduled for a parliamentary vote on 24 November 2026, proposes deferring this obligation by a further year: fiscal year 2028, first submission in 2029 (VATupdate, 12 October 2026, RTC Suite).
This potential deferral does not mean SAF-T accounting has been dropped. It means the preparation window has been extended. Companies already operating with a certified ERP whose accounting is structured according to the Portuguese chart of accounts (POC) will face no major project. Those consolidating their Portuguese subsidiary into a non-localised group ERP will, however, need to plan for data extraction and reformatting.
ATCUD and QR Code: Two Mandatory Codes on Every Invoice
The ATCUD: The Unique Document Code
The Código Único de Documento (ATCUD) is mandatory on all invoices and fiscally significant documents since 1 January 2023 (SNI Technology). It is structured in two parts separated by a hyphen:
- A series validation code (minimum 8 alphanumeric characters), assigned by the AT when a company registers a billing series
- A sequential number representing the document’s position within its series
The full format printed on the invoice is: ATCUD:XXXXXXXX-NNNN
To obtain the validation code, the company must declare its series to the AT via a dedicated web service, specifying the document type (per the SAF-T PT structure), the sequence start number, and the effective date. The AT returns a validation code that remains valid for the entire fiscal year.
A common trap in multi-entity setups or during ERP migrations: each billing series must be registered separately with the AT. A series created in the new ERP but not registered with the AT produces non-compliant invoices. This is one of the most frequent sources of error during ERP system cutovers in Portugal.
The QR Code: Mandatory Since 2021
The QR Code on invoices has been mandatory since January 2021 for large companies and since 2022 for all entities. It encodes the issuer’s tax identifier, the ATCUD, the net amount, VAT, and the certified software identifier (Storecove, ATCUD & QR Guide).
Do not confuse ATCUD and QR Code: both are required and coexist on the invoice. The ATCUD is a text identifier printed in plain text; the QR Code is the electronic transmission vehicle for the same set of information, used for automated verification and reconciliation.
Electronic Signatures on PDF: The 2027 Tipping Point
The Current Situation
Until 31 December 2026, a PDF invoice issued by AT-certified software is legally acceptable as an electronic invoice in Portugal without a Qualified Electronic Signature (QES). This is the tolerance regime that has been in place for several years, maintained by the 2026 Finance Act.
What Changes (or Should Change) in 2027
Since 2021, Portuguese legislation has provided that a PDF invoice would only have legal standing as an electronic invoice if accompanied by a Qualified Electronic Signature (QES) issued by a qualified trust service provider (within the meaning of eIDAS). This requirement has been postponed every year.
The 2026 Finance Act (Lei 73-A/2025) had finally set this obligation for 1 January 2027. The 2027 budget proposal, submitted in October 2026, proposes a further one-year extension, pushing the deadline to 1 January 2028 (RTC Suite, October 2026). The final vote is scheduled for 24 November 2026.
What this means for your ERP: if the proposal is adopted, PDFs remain valid without QES until end of 2027. If it is not, QES becomes mandatory from 1 January 2027. In either case, implementing qualified electronic signatures on invoicing flows is a project that ERP teams must plan for, even if the date shifts.
QES implementation involves:
- A subscription with a qualified trust service provider (the AT website publishes the eIDAS list)
- Integration into the invoice generation process within the ERP or e-invoicing platform
- Compatibility testing with the formats accepted by business partners
B2G: Structured E-Invoicing Mandatory for All in 2027
Structured electronic invoicing to public sector bodies (B2G) has been mandatory for large companies since January 2021. It becomes mandatory for SMEs, small businesses, and micro-enterprises from 1 January 2027.
The required format is CIUS-PT, the Portuguese national profile of the European standard EN 16931, delivered in UBL 2.1 or UN/CEFACT. The central platform is the AT infrastructure, also accessible via the Portuguese Peppol network (FE-AP) or certified point-to-point EDI connections.
For European companies that invoice Portuguese public sector clients — local authorities, hospital trusts, parapublic entities — this 2027 obligation is concrete and cannot be deferred.
What Your ERP Needs to Cover
Immediate Verification Checklist
| Obligation | In Force Since | Your ERP Must… |
|---|---|---|
| AT-certified software | 2008 (extended 2023) | Be certified or use a certified connector |
| QR Code on invoices | 2021-2022 | Automatically generate the AT QR Code |
| ATCUD on invoices | 1 Jan 2023 | Register AT series + generate the code |
| Monthly SAF-T billing | 1 Jan 2023 | Export SAF-T v1.04+ file before the 5th of each month |
| B2G CIUS-PT (SMEs) | 1 Jan 2027 | Issue in UBL 2.1 CIUS-PT via FE-AP or Peppol |
| QES on PDF | 1 Jan 2027 (or 2028) | Integrate a qualified signature workflow |
| SAF-T accounting | 2028 (or 2029) | Export accounting data in SAF-T PT format |
Major ERP Solutions and Their Portugal Compliance Coverage
Cegid Primavera is the dominant vendor for the Portuguese SME market. Primavera BSS, founded in Portugal, joined the Cegid group following the acquisition of Grupo Primavera completed in September 2022. AT compliance is native: software certification, ATCUD, QR Code, monthly SAF-T billing, and B2G module in UBL 2.1 CIUS-PT. Cegid Primavera also acquired PHC Software in January 2025, another major Portuguese vendor serving the micro-enterprise and SME segment (Cegid Primavera press release).
SAP S/4HANA covers Portuguese compliance through the SAP Localization Hub for Portugal, or via specialised partner add-ons for AT certification. Coverage quality depends on the version and the local implementation partner.
Microsoft Dynamics 365 Finance includes an integrated Portugal localisation (managed directly by Microsoft), covering AT certification, ATCUD, QR Code, and SAF-T billing.
Odoo: Portuguese compliance relies on community modules (OCA — Odoo Community Association) and modules developed by local partners. Maturity varies by version and the maintenance level of the installed PT module. An audit of the installed PT module is advisable before any regulatory deadline.
Sage: depending on the version (Sage 50, Sage 200, Sage X3), Portuguese coverage varies. Sage 50 Portugal includes native AT compliance; Sage X3 often requires specific configuration or partner development for the Portuguese market.
Action Plan for CIOs and CFOs
90 Days Before Each Deadline: An 8-Point Checklist
- Verify AT certification of the billing software used in Portugal — the public list is available on the AT website
- Audit billing series registered with the AT: every series active in the ERP must have a valid AT validation code
- Test SAF-T billing file generation for the past three months and validate against the AT’s SVAT tool
- Map current PDF flows to Portuguese public sector clients and assess the impact of migrating to CIUS-PT
- Identify a QES provider: ask your ERP vendor for the qualified signature integration workflow
- Audit subsidiaries and branches: non-resident entities with a Portuguese VAT number are subject to the same obligations as residents
- Document the monthly close process to ensure SAF-T billing is generated and submitted to the AT before the 5th of each month
- Set up a regulatory alert on the Portuguese state budget (parliamentary vote on 24 November 2026) to adjust the QES project timeline
Questions to Ask Your ERP Integrator
- Which SAF-T (PT) version does our ERP generate? Is it compliant with the AT’s v1.04 schema?
- Is the ATCUD generated automatically via the AT web service, or does it require manual input?
- What is the integration path for QES on PDF invoices issued by our ERP?
- Does the Portugal localisation support CIUS-PT format for B2G invoicing?
- How will SAF-T accounting data be extracted when the time comes — native export or additional module?
For a broader view of European compliance timelines, read our guide on mandatory e-invoicing across Europe: the ERP roadmap for 2027 and our analysis of e-invoicing obligations in the Baltic States and Slovakia 2026-2028. On neighbouring Spain, our guide to the SPFE platform and Spanish B2B e-invoicing completes this Iberian picture.
