E-invoicing in Portugal has three moving parts: SAF-T (PT) reporting to the tax authority (AT), structured invoices to the public sector through ESPAP, and PDF invoices — valid to 31 December 2026, and needing a qualified electronic signature or seal from 1 January 2027. GoRoute covers all three from one e-invoicing platform, with AT-certified billing software integration.
Partly. Since 1 January 2026, micro, small and medium enterprises supplying the Portuguese public sector must send structured electronic invoices through ESPAP, under Decree-Law 13-A/2025. Between businesses, PDF invoices stay valid to 31 December 2026; from 1 January 2027 a PDF invoice needs a qualified electronic signature or seal.
The 1 January 2027 date is the one to plan against: the 2026 State Budget deferred it from 2026, so a PDF you send today is still a valid invoice, and the same PDF sent in January 2027 is not unless it is signed or sealed. Portugal sits alongside every other 2026 deadline in our e-invoicing mandates tracker.
Portugal asks five separate things, and they are routinely mistaken for one. Two are about the document, one is about the program that issues it, one is about reporting to the tax authority, and one applies only when the customer is a public body. Each carries its own date, and the sections after this table take them one at a time.
| Obligation | Applies to | Date |
|---|---|---|
| Certified billing software | The program that issues the invoice, which must be certified by the Autoridade Tributária (AT) | In force today |
| ATCUD on the document | Invoices in any format, including PDF | Since 2023 |
| SAF-T (PT) invoicing file | Businesses keeping electronic records, reporting to AT | Monthly, in force today |
| Structured invoice through ESPAP | Suppliers to the public sector — micro, small and medium enterprises, under Decree-Law 13-A/2025 | Since 1 January 2026 |
| Qualified signature or seal | PDF invoices, which stay valid as they are until 31 December 2026 | From 1 January 2027 |
SAF-T (PT) is Portugal's Standard Audit File for Tax purposes: an XML export of accounting and invoicing data for review by the tax authority, the Autoridade Tributária (AT). The invoicing file is submitted monthly. It is a reporting obligation, and it is separate from the format your invoices themselves take.
That separation is the part worth holding on to, because it explains something that otherwise looks like a contradiction. A business in Portugal can send its customer an ordinary PDF invoice and still owe AT a structured monthly file describing that same invoice. One is the document the customer receives; the other is the record the authority reads. They coexist through 2026 without either cancelling the other.
It also places Portugal in the wider map. Our tracker classifies Portugal as post-audit plus SAF-T: the authority reads the data after the invoice has been exchanged, rather than standing in the middle of the exchange and clearing each document before it reaches the buyer. Countries running a clearance model impose a very different integration on a finance system, because nothing reaches the customer until the authority has answered. Portugal does not work that way today, and none of the dates on this page changes that. The country-by-country view of how these models differ is the wider comparison.
Two things follow for anyone planning a project. Moving from PDF invoices to structured ones does not retire the SAF-T obligation — it changes what the customer receives, not what AT is owed. And sending invoices over the Peppol network does not retire it either: Peppol is a delivery route to your customer's finance system, not a filing channel to a tax authority. A Portugal project that treats "we are on Peppol now" as the end of the work has left the monthly file unowned.
One thing this page deliberately does not state is the day of the month the invoicing file falls due, or how a correction to an already-submitted file is handled. AT sets both, and AT is where to confirm them — the link at the foot of this page goes there.
ATCUD is a unique document code required on Portuguese invoices since 2023, in any format including PDF. It has two parts: a series code obtained from AT, and the document's sequential number within that series. Together they give every document issued in Portugal an identifier nothing else shares.
The order of operations is what catches teams out. The series code comes from AT, which means the series exists as far as the authority is concerned before the first document in it is issued. It is not a value a billing system can work out for itself from the invoice number, the year or the company's tax number. Whatever issues your invoices has to hold the code AT returned against that series and print both parts — series code and sequential number — on every document it produces.
ATCUD is indifferent to what the invoice looks like. It sits on a PDF and it sits on a structured invoice, and it has done since 2023. None of the dates further down this page removes it: the qualified electronic signature or seal that PDFs need from 1 January 2027 is an addition rather than a replacement, so an invoice sent in 2027 needs both.
It is also not the SAF-T file and not the certification of the billing program. Three obligations, three mechanisms — and, in almost every real installation, one system producing all three. That is why the choice of billing system carries more weight in Portugal than it does in most countries, and why the next section is about the software rather than the document.
Software certified by the Autoridade Tributária. The requirement attaches to the program, not to the invoice — which is exactly why it gets missed by anyone reading a list of document rules and assuming that is the whole obligation.
In practice, the certified program is where the rest of the Portuguese picture is produced. It holds the registered series and prints the ATCUD. It produces the invoicing data that feeds the monthly SAF-T file. Portuguese invoices carry a digital signature on the document today, ahead of and separate from the qualified signature or seal that PDFs will need from 1 January 2027. Issuing invoices around the side of that program — out of a spreadsheet, a payment tool or a new system nobody checked — is therefore not a small change. It moves three obligations at once.
This is also the honest boundary of what GoRoute does. We are a Peppol certified Access Point and SMP provider, and what this page offers is the e-invoicing layer around your billing system: SAF-T (PT) export, ATCUD generation, signing, Portuguese IVA handling, submission to the public sector through ESPAP, and delivery across the EU over Peppol. We connect to the billing software you already run rather than replacing it — our Odoo integration is one example of that shape of connection, and the API is the general case for a system we have not met before.
Which specific programs hold AT certification is not something to take from any vendor's website, including this one. The authority publishes that position and the authority is the place to check it, whether you are choosing a system or inheriting one.
As a structured electronic invoice in CIUS-PT format, through ESPAP. Micro, small and medium enterprises supplying the Portuguese public sector have been in scope since 1 January 2026, under Decree-Law 13-A/2025. This is the one obligation on this page whose date is already behind us.
CIUS-PT is Portugal's Peppol specialisation. A specialisation is a national narrowing of a shared format: the same underlying structured invoice that the rest of the network exchanges, with a national rule set layered on top governing which fields are mandatory and what values they may carry. If the document itself is unfamiliar, what a UBL invoice is is the shorter read, and how the Peppol network works covers the delivery side.
The practical consequence is that a PDF is not the deliverable here. A public body needs a document its systems can process without a person retyping it, in the format it expects, arriving by the route it actually reads. The buyer is identified by NIF, the Portuguese tax number, which is why validating the NIF belongs before you send rather than after a rejection comes back.
For a supplier already connected to Peppol this is less new work than it sounds: the network and the base format are shared with the rest of Europe, and Portugal's contribution is the national rule set and the destination. For a supplier connected to nothing, it is the piece to start with — not because it is the largest, but because it is the only one whose deadline has already passed.
A PDF invoice is valid in Portugal exactly as it is until 31 December 2026. From 1 January 2027 it needs a qualified electronic signature or seal. The 2026 State Budget deferred that requirement to this date, and it is the only date on this page still ahead of us.
Put at its plainest: the same file, sent on two consecutive days, is a valid invoice on 31 December 2026 and is not one on 1 January 2027 unless it has been signed or sealed. That is the whole change. It is worth saying that precisely, because it is often reported as Portugal mandating e-invoicing in 2027, and that is not what the rule says — the rule is about what a PDF must carry, not about abolishing the PDF.
What does not change on that date is everything above it. ATCUD stays on the document. The monthly SAF-T file is still owed. The billing program still has to be certified. And the word doing the work in the requirement is qualified: Portuguese invoices already carry a digital signature today, and the 2027 requirement names a separate thing.
Which leaves two projects, and your own document mix decides which is the smaller. You can add qualified signing to the PDF flow you already run, or you can move the flow to structured invoices — the second being a route you are partly on already if you supply the public sector through ESPAP. The runway from today is a little over four months. That is enough for either if it starts now, and not enough for either if it starts in December, which is when everybody else will be asking.
Which of the two Portuguese routes you are looking at is decided by your customer, not by where you are. A Portuguese public body reads structured invoices in CIUS-PT delivered through ESPAP. A Portuguese business customer sits under the PDF calendar above: valid as it stands to 31 December 2026, and needing a qualified electronic signature or seal from 1 January 2027.
| Your customer | What reaches them | The date behind it |
|---|---|---|
| A Portuguese public body | A structured invoice in CIUS-PT, through ESPAP | Micro, small and medium suppliers since 1 January 2026 (Decree-Law 13-A/2025) |
| A Portuguese business | A PDF invoice, valid as it stands; or a structured invoice if you would rather not sign PDFs | PDFs valid to 31 December 2026; qualified signature or seal from 1 January 2027 |
Two things are worth settling before the first invoice goes out, and neither needs a legal opinion. The first is the customer's NIF, because it identifies them and because an invalid one is found faster by a validation step than by a rejection two weeks later. The second is the route: how the document physically reaches them. For a public body that route is ESPAP. For a business customer it is whatever the two of you agree, and if that is Peppol, then CIUS-PT is a specialisation of the same document you are already sending elsewhere in Europe rather than a new format to learn.
There is one question this page will not answer for you. Whether the issuer-side obligations above — certified billing software, the registered series and its ATCUD, the monthly SAF-T file — reach a supplier established outside Portugal is not something to take from a vendor's page. It is the first question to put to the Autoridade Tributária, and the answer is worth having in writing before a project plan is built on it.
If Portugal is one country in a larger European rollout rather than a one-off, the neighbouring calendars matter as much as this one: France and Italy both run models different from Portugal's, and the global view sets all of them side by side.
SAF-T (PT) is Portugal's Standard Audit File for Tax purposes. All businesses must maintain electronic records and export them in SAF-T format for tax authority review.
Billing software must be certified by Autoridade Tributária (AT).
SAF-T invoicing file must be submitted monthly to AT.
Unique document code required on all invoices from 2023.
SAF-T (PT) Export
XML format per Portuguese specifications
Digital Signature
RSA signature on documents today; qualified signature or seal on PDFs from 1 Jan 2027
B2G via ESPAP
Public sector invoicing through ESPAP portal
NIF Validation
Portuguese tax number verification
Automatic SAF-T (PT) file generation for AT submission.
RSA cryptographic signature on invoice documents, and qualified signatures or seals ready for the 1 January 2027 requirement on PDFs.
Full support for 23%, 13%, 6% VAT rates and exemptions.
Submit invoices to Portuguese public sector through ESPAP.
SAF-T (PT) exports, ATCUD codes, CIUS-PT invoices to ESPAP, and Peppol delivery across the EU.
Official source: Autoridade Tributária — Portugal's tax and customs authority. Always confirm current obligations against the authority directly.
Related reading: E-invoicing mandates 2026: a country-by-country tracker — Portugal's dates alongside every other mandate landing this year.
SAF-T (PT) is Portugal's Standard Audit File for Tax purposes: an XML export of accounting and invoicing data for review by the tax authority (AT). The invoicing file is submitted monthly. SAF-T is a reporting obligation and is separate from the format your invoice takes, which is why a PDF invoice and SAF-T reporting coexist through 2026.
ATCUD is a unique document code required on Portuguese invoices since 2023, in any format including PDF. It combines a series code obtained from AT with a sequential number, so every document carries a unique identifier. The 2027 signature requirement does not replace it: an invoice needs both.
Yes. Suppliers to the Portuguese public sector must send structured electronic invoices through the ESPAP portal in CIUS-PT format, Portugal's Peppol specialisation. Micro, small and medium enterprises have been in scope since 1 January 2026 under Decree-Law 13-A/2025.
Yes, until 31 December 2026. A PDF invoice is valid in Portugal exactly as it is up to that date. From 1 January 2027 it needs a qualified electronic signature or seal, a requirement the 2026 State Budget deferred to then. Nothing else changes on that date: the ATCUD code stays on the document, the monthly SAF-T file is still owed, and the billing program still has to be certified.
CIUS-PT is Portugal's Peppol specialisation: the same structured invoice exchanged across the Peppol network, with a national rule set on top governing which fields are mandatory and what values they may carry. It is the format for invoices sent to the Portuguese public sector through ESPAP.
Yes, and the customer decides the route. A Portuguese public body needs a structured invoice in CIUS-PT through ESPAP. A Portuguese business can be sent a PDF, valid as it stands to 31 December 2026 and needing a qualified electronic signature or seal from 1 January 2027. Whether the issuer-side obligations — certified billing software, the registered series and its ATCUD, and the monthly SAF-T file — reach a supplier established outside Portugal is a question for the Autoridade Tributária rather than for a vendor.
