Country deep dive
Portugal's regime is genuinely unusual among the countries in this tracker: there's still no general B2B or B2C e-invoicing mandate, but a dense layer of certified-software, security, and reporting requirements applies to every invoice regardless — and a real structured-format mandate exists for public-sector supply.
The foundation of Portugal's modern fiscalization system, well before any e-invoicing mandate existed — this file format underpins the reporting obligations that came later.
The true start of Portugal's modern fiscal system: all invoices, regardless of format, must be issued using software certified by the Autoridade Tributária (AT).
Establishes the legal basis for Portugal's B2G e-invoicing regime, implementing EU Directive 2014/55/EU into national law.
Public administration entities become obliged to receive and process structured e-invoices, via the centralised eSPap-operated platform or a designated service provider.
Large companies supplying public administration bodies must issue structured e-invoices in the national CIUS-PT format (a Portuguese implementation of EN 16931, via UBL 2.1 or CEFACT CII), transmitted through the eSPap-operated FE-AP platform or another approved channel. Portugal has no general B2B or B2C e-invoicing mandate — this requirement applies specifically to public-sector supply.
Every invoice — paper or electronic, B2G or otherwise — must carry a QR code enabling validation. The ATCUD unique document code requirement follows a year later, becoming mandatory from 1 January 2023.
Refines and extends the legal basis established by Lei n.º 111-B/2017.
Confirmed via the 2026 State Budget (approved 27 November 2025): PDF invoices issued by certified software, carrying ATCUD and a QR code, stay legally valid without a Qualified Electronic Signature until this date.
The CIUS-PT structured e-invoicing requirement for public-sector suppliers, previously applying only to large companies, now extends to small, medium, and micro-enterprises. Separately, regardless of company size or whether B2G applies, all invoices — paper or electronic — must already be issued using AT-certified software and carry an ATCUD code, a QR code, and a hash chain for authenticity.
PDF invoices in B2B and B2C transactions will require a Qualified Electronic Signature from an EU-listed trust service provider to remain legally valid — deferred from an original 2026 date via the 2026 State Budget. Until 31 December 2026, PDF invoices issued by certified software with ATCUD and a QR code remain valid without a QES. This layer applies on top of, not instead of, the certified-software/ATCUD/QR/SAF-T requirements already in force.
The first mandatory full annual accounting SAF-T submission, covering 2027-year transactions, becomes due — itself deferred from an earlier 2026 timeline via the same State Budget process.
Portugal runs two genuinely separate tracks: a real structured-format mandate for B2G, and a lighter-touch security-and-traceability regime that applies to everything else.
CIUS-PT is Portugal's national adaptation of the EU standard — implementations should target UBL 2.1 CIUS-PT specifically, not a generic EN 16931 build.
Don't mistake "no structured-format mandate" for "no requirements" — the certified-software and document-security layer applies to every invoice regardless of format.
This exists specifically because PDFs, unlike structured XML, can be altered after issuance unless cryptographically sealed — QES is Portugal's answer to that gap.
The full accounting SAF-T file is a materially bigger scope than the monthly billing file already in force — don't assume existing SAF-T compliance covers it automatically.
The single most important thing to understand about Portugal: there is no clearance step, and no general transmission mandate outside B2G — enforcement instead relies on certified software and reporting, not real-time validation.
Suppliers to public bodies must connect to FE-AP or an equivalent approved channel — this is the one place in Portugal's regime with a genuine transmission requirement.
A genuinely different model from clearance-model peers in this tracker — there's no tax-authority validation step before an invoice is legally issued.
This is the requirement most likely to actually catch a business out — it's easy to focus on B2G/QES timelines and overlook that certified software has been mandatory since 2010–2011.
Compliance here means working through several independent, layered requirements — not a single registration step.
This applies to every business, regardless of size or whether B2G invoicing applies at all — using uncertified software makes an invoice invalid outright.
Mandatory for every company size from 1 January 2026 — connect to FE-AP or an approved alternative channel.
Required since 2022, regardless of B2G status or invoice format — check this is genuinely automated, not manually applied.
Already a live requirement — don't conflate this with the separate, larger full accounting SAF-T file due from 2028.
Needed ahead of the 1 January 2027 deadline for PDF invoices — this is a procurement step, not a software configuration option, so start it well in advance.
Covers 2027-year transactions — a materially larger scope than the monthly billing file already in force.
Portugal's enforcement model works differently from a clearance-model country's fine schedule — the real risk is an invoice being treated as invalid outright, not a graduated penalty for late compliance.
Other countries in the same region, ordered by their next dated milestone. Each links to a full briefing.