SAF-T Portugal: what it is, who files, deadlines and rejections

What SAF-T (PT) is

SAF-T (PT) is Portugal's version of the OECD Standard Audit File for Tax: an XML file, in a structure defined by the tax authority (AT), that carries your invoicing and accounting data. The structure in force is version 1.04_01 (official XSD and what changed in 2022).

In practice "submitting the SAF-T" usually means the monthly billing SAF-T: the file that reports the invoices you issued the previous month. The accounting SAF-T uses the same structure but covers the full ledger; today AT can request it during an inspection, and annual submission becomes mandatory in 2028, for the 2027 financial year.

Who must submit

Under Decree-Law n.º 198/2012 (article 3), anyone with a seat, permanent establishment or tax domicile in Portugal who carries out operations subject to VAT there must communicate the invoices they issue to AT. That includes Portuguese subsidiaries and branches of foreign groups, whatever accounting system the group uses.

A month with no invoices still needs a communication: you tell AT that there was no invoicing that month.

How: file or webservice

There are two ways to communicate invoices, and you pick one, not both:

Monthly SAF-T file: your certified billing software exports the file and you upload it in the e-Fatura area of the Portal das Finanças.
Webservice: the software sends each invoice to AT automatically, close to real time.

Most small and mid-sized companies use the monthly file, and that is where rejections happen.

When: day 5 of the following month

The billing SAF-T is due by day 5 of the month after the invoices were issued. When day 5 is a Saturday, Sunday or public holiday, the deadline moves to the next working day. See the current deadline and the next twelve.

The deadline has moved earlier twice: it was day 25 when communication started, day 12 from January 2020, and day 5 from January 2023 (State Budget for 2022).

Fines

Missing or late communication is a tax offence under the General Regime for Tax Infractions (RGIT, article 117). The fine ranges from €150 to €3,750, and the limits are doubled for companies (article 26, n.º 4), so €300 to €7,500 per infraction. Fines are reduced when you regularise on your own before AT opens proceedings, which is one more reason to fix a rejected file quickly.

Why files get rejected

AT often answers a bad file with a generic "ficheiro inválido" (what each AT message means). The usual causes:

Encoding. AT expects Windows-1252; many systems export UTF-8. How to fix the UTF-8 error.
A byte order mark (BOM) before the XML declaration.
NIF check digits on customers or suppliers. Check a NIF.
ATCUD format, mandatory on every document since 2023. Check an ATCUD.
Header dates and documents dated outside the reporting period.

Systems built outside Portugal (international ERPs, group-wide accounting platforms) hit these more often, because the Portuguese export is a small module in a large product. Exporting from SAP? What to check.

What is changing

1 January 2027: PDF invoices exchanged outside EDI need a qualified electronic signature (QES) to count as electronic invoices. This concerns the invoices themselves, not the SAF-T structure.
2028: first mandatory annual submission of the accounting SAF-T, for 2027. It has been postponed several times, so watch for further changes.
Schema: as of October 2026, AT has not announced a new SAF-T version.

A monthly routine that avoids last-minute surprises

By the 1st: close last month's invoices in your billing software; no drafts left open.
By the 3rd: export the billing SAF-T.
By the 4th: validate the file and fix what it finds.
By the deadline: upload it on the Portal das Finanças and keep the submission receipt.

Set the reminder for the 3rd, not the 5th. Two days of margin turn a rejection into a quick fix instead of a missed deadline.