Electronic invoicing guide
Portugal
Digital reporting requirements
Post-audit: B2G
Reporting: B2B, B2C or SAF-T PT
Obligatory
B2G: Mandatory issuing and receiving.
B2B: E-Invoicing Voluntary, Periodic Reporting Mandatory
Authority
AT – Autoridade Tributária e Aduaneira
Platform
Portal BASE (general eProcurement)
Plataforma Eletrónica de Compras (eSPap platform)
Format
UBL 2.1 “CIUS-PT” and CEFACT “CIUS-PT”
Storage time
10 years
Reporting and processes
Periodic Reporting:
Mandatory communication of the elements of all invoices (B2B, B2C, B2G) to the AT (Tax Authority) in SAF-T(PT) (XML) format.
Submission methods:
- Monthly submission of the SAF-T(PT).
- Near real-time transmission via web service (certified software).
- Manual upload to the AT portal (micro-enterprises).
It is mandatory to be able to generate the accounting SAF-T and provide it to the AT in case of an inspection. The obligation to submit it systematically on an annual basis has been postponed several times. Under the 2026 State Budget (approved on 27 Nov 2025), the first mandatory annual accounting SAF-T applies to 2026 operations, with delivery due in 2028.
Processes
- Software certified by the AT. Mandatory if you invoiced more than 50,000 euros in the prior year or keep organized accounting records.
- Register the series with the AT before issuing the first invoice. It returns a validation code.
- Issue with the mandatory elements. The software automatically adds: sequential numbering, ATCUD, QR code, and hash, plus the data required under Article 36 of the CIVA.
- Format and channel, depending on the recipient.
- B2G: CIUS-PT mandatory, via FE-AP, Peppol, or that entity’s own channel.
- B2B/B2C: free format (paper, PDF, or structured), if accepted by the recipient.
- Ensure authenticity and integrity.
- Paper: certified software, ATCUD, QR code, and audit trail are sufficient.
- Electronic (PDF, XML, Peppol): an audit trail is not enough. You need a qualified signature, qualified seal, or EDI.
- PDF without a seal is valid until 31 Dec 2026. From 1 Jan 2027, a seal is required.
- Report to the AT via the invoicing SAF-T.
- Archive for 10 years, ensuring integrity and legibility. Electronic archiving is permitted.
Upcoming legislative changes
As of today, PDFs used as invoices in B2B transactions remain valid without a qualified electronic signature or seal until 31 December 2026, provided they meet the other requirements (certified software, ATCUD, QR code, etc.).
PDF files will be accepted and considered electronic invoices for all purposes provided for under tax legislation until 31 December 2026, without needing to be signed with a Qualified Electronic Signature (QES).
From 1 January 2027, all invoices that are not created and transmitted in structured format (non e-invoice), including PDFs, must be signed with a QES (Qualified Electronic Signature) to be considered valid for tax purposes.
The structured e-invoice remains voluntary for B2B and is only mandatory for B2G.
Links of Interest and documents
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