Quick answer: PDF invoices continue to be accepted as electronic invoices for all tax purposes until 31 December 2026. The submission of the accounting SAF-T (PT) file has been postponed once again, becoming mandatory for the 2027 periods onwards, with submission in 2028. Until then, ATCUD, QR codes, and monthly invoice reporting remain in force.
If your company has been delaying the modernisation of its invoicing processes because "the deadline always gets extended", it is worth taking a close look at the upcoming timeline. The delays have been real, but the direction of travel is unmistakable.
In summary
| Obligation | Current status |
|---|---|
| Monthly reporting of invoices to the AT (*Autoridade Tributária* – Tax and Customs Authority) | In force, by the 5th of the following month |
| QR code on invoices | In force |
| ATCUD (unique document code) | In force |
| PDF invoices accepted as electronic invoices | Until 31 December 2026 |
| Accounting SAF-T (PT) | 2027 periods onwards, submission in 2028 |
| Electronic invoicing with the State (B2G) | In force for large, medium and small enterprises |
The end of the simple PDF: what is really at stake
For years, the standard practice in Portugal was to send PDF invoices by email. From a technical perspective, such an invoice is not an electronic invoice: it is merely a digital image of a paper invoice.
A true electronic invoice is issued, transmitted and received in a structured format that allows automated processing by the recipient's system, guaranteeing the authenticity of origin and integrity of content, typically through a qualified electronic signature, qualified electronic seal or EDI.
What the law has been doing is extending, year after year, the acceptance of PDFs as an equivalent. The current extension runs until 31 December 2026.
What this means for a company in 2026:
- Nothing changes immediately regarding ongoing B2B relationships.
- However, preparation of processes should begin now, as the transition requires changes to software, approval workflows, and often contracts with clients and suppliers.
Accounting SAF-T: what it is and why it was postponed again
The accounting SAF-T (PT) is a standardised file that exports a company's complete accounting records in a format readable by the *Autoridade Tributária*, enabling the pre-population of the *IES* (*Informação Empresarial Simplificada* – Simplified Corporate Information) and providing significantly enhanced auditing capabilities.
Invoicing SAF-T already exists and has been mandatory for years. What has been repeatedly postponed is the accounting SAF-T.
The current schedule: applicable to 2027 periods onwards, to be submitted in 2028 or in subsequent periods.
In practice, this gives companies and accounting firms about a year and a half to ensure that charts of accounts, classifications, and document management are prepared for standardised export. This is by no means too much time. Companies with messy accounting histories will need every bit of it.
ATCUD and QR codes: the details still causing trouble
Both are currently in force and are frequently implemented incorrectly.
ATCUD is the unique document code, consisting of the series validation code (obtained from the AT) and the sequential document number within that series. It must appear on all tax-relevant documents.
Common errors:
- Document series reported to the AT but not properly linked within the software.
- Reusing series across financial years without new validation.
- Internal documents issued outside certified software.
QR code must be present on all invoices and equivalent documents, allowing the buyer to record the invoice on the e-fatura portal by scanning it with a smartphone.
Electronic invoicing with the State (B2G)
For public contracts, electronic invoicing in a structured format is already mandatory. Any business supplying goods or services to public entities must issue an e-invoice through the designated channels, complying with the applicable data model.
This is where many SMEs end up taking their first step into true e-invoicing. Those who are already B2G compliant are halfway there for B2B.
Recommended preparation plan for 2026 and 2027
By September 2026
- Confirm that your invoicing software is certified by the AT and up to date.
- Verify document series, ATCUD and QR codes on all issued document types.
- Identify which clients already require a structured format.
By December 2026
- Test issuing invoices in a structured format with at least one client and one supplier.
- Assess the need for a qualified electronic signature or qualified electronic seal.
- Review the process for receiving and digitally archiving supplier invoices.
During 2027
- Align the chart of accounts and supporting documents with the accounting SAF-T requirements.
- Correct inconsistent accounting classifications before they become visible in a standardised file.
- Close 2027 with the file already tested, rather than waiting for the submission deadline in 2028.
Why this really matters for an SME
It is tempting to view these rules as additional bureaucracy. In practice, there are three concrete consequences:
- Less room for undetected accounting errors. A standardised file makes inconsistencies immediately visible.
- Real reduction in administrative costs when structured invoicing replaces manual data entry.
- Increased audit capabilities for the AT, through automated cross-referencing between invoicing, accounting, and tax returns.
Companies with well-organised accounting stand to gain from this evolution. Others will remain exposed.
Frequently asked questions
Can I continue sending PDF invoices by email in 2026?
Yes. PDF invoices are accepted as electronic invoices for tax purposes until 31 December 2026.
When is the accounting SAF-T mandatory to submit?
For 2027 periods onwards, with submission in 2028 or in subsequent periods.
Has the invoicing SAF-T also been postponed?
No. Invoicing SAF-T is already mandatory and remains in force, with monthly invoice reporting to the *Autoridade Tributária*.
Does my company need a qualified electronic signature?
It depends on the format adopted. Authenticity and integrity can be guaranteed by a qualified electronic signature, a qualified electronic seal, or EDI with appropriate controls.
Is a small business that only invoices end consumers also covered?
Yes, regarding certified software, ATCUD, QR codes, and invoice reporting. Structured format requirements have a greater impact on B2B and B2G relationships.
Want to prepare your company in advance?
Grupo Your supports businesses through the digital transition of their tax obligations, from invoicing software to SAF-T-ready accounting organisation. Anticipating costs less than correcting. Get in touch with us.
Related articles:
- Invoice Reporting: Deadline Extended to 8 April
- IRC (*Imposto sobre o Rendimento das Pessoas Colectivas* – Corporate Income Tax) Guide 2026: Rates, Tax Benefits and Regional Regimes
- How to Choose an Accounting Firm in Portugal: The Complete Guide
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