Retail & commerce · Portugal · Tax compliance

CIUS-PT & SAF-T — Portugal's structured-invoice cliff PMEs can't dodge.

For the Lisbon shopkeeper whose till prints to a Word document, the Porto café whose owner sends invoices from a Gmail thread, the Algarve guesthouse whose contabilista visits once a month with a USB stick, and the Braga oficina whose POS is a fifteen-year-old Windows machine — Portugal's e-invoicing and tax-reporting regime has been bolted on in layers, each promising to be "the last one." Since January 2023 every invoice issued from AT-certified software must carry an ATCUD unique-document identifier and a QR code, and the SAF-T (PT) billing file must reach the Autoridade Tributária by the 5th of the following month. From 1 January 2026 B2G e-invoicing in the structured CIUS-PT format becomes mandatory for SMEs (after multiple postponements). From 1 January 2027 a Qualified Electronic Signature on PDF B2B/B2C invoices ends the grace period during which "PDF-by-email" was treated as compliance. And the accounting SAF-T (PT) covering FY2026 becomes mandatory to file in 2027–2028 — on top of certified billing software, a digital archive, QES credentials, and a contabilista whose schedule is now everyone's schedule.

TL;DR

What hurtsA layered, repeatedly-postponed Portuguese stack — ATCUD + QR + monthly SAF-T(PT) live since January 2023, B2G CIUS-PT XML mandatory for SMEs from 1 January 2026, QES on PDF B2B/B2C invoices from 1 January 2027, accounting SAF-T(PT) for FY2026 filed 2027–2028 — that forces sole traders and small shops to coordinate AT-certified billing software, a digital archive, qualified-signature credentials and a contabilista on a budget that was never staffed for any of it.
How bigLive since January 2023: ATCUD + QR + monthly SAF-T(PT) by the 5th of the following month. New cliffs: 1 January 2026 B2G CIUS-PT for SMEs; 1 January 2027 QES on PDF B2B/B2C; 2027–2028 accounting SAF-T(PT) for FY2026 — all on AT-certified software only.
The response3 retail companies in Portugal cataloged below as a public response — each verified to self-market in this exact niche.

01The pain

The European Commission's DG DIGITAL eInvoicing-Country page for Portugal — published by the EU directorate that maintains the per-Member-State reference for Directive 2014/55/EU implementation — sets out the regime in plain regulatory language. Portugal's e-invoicing legal frame is anchored in Decreto-Lei 123/2018 and Decreto-Lei 28/2019, and CIUS-PT (the Portuguese Core Invoice Usage Specification, built on the EN 16931 European standard with UBL 2.1 syntax) is the structured XML format public administrations and SMEs must use for B2G transactions. The same page records the staging that operators have inherited from successive postponements: large enterprises were caught earlier, micro and small operators (PMEs) have been pulled forward each year, and the operating bodies — eSPap on the central-administration side, Autoridade Tributária on the tax side — operate the network and the SAF-T(PT) submission channels respectively. For a Portuguese SME, the EC page is the document that converts "we hear there's a new e-invoicing rule" into the four moving parts an operator actually has to wire together: AT-certified software, ATCUD series communication, monthly SAF-T(PT) submission, and CIUS-PT XML for B2G.¹

The Group Seres coverage — published by a multinational EDI and e-invoicing service provider whose Portuguese desk tracks every postponement of the structured-invoicing rule — captures the operational shape of the 2026 cliff as the trade press inherits it. Trade press records that the 1 January 2026 deadline for B2G CIUS-PT for SMEs is the latest in a chain of postponements: previous schedules slipped multiple times under pressure from operators and software houses that argued certified-vendor capacity could not cover the long tail of micro-firms in time. The same coverage frames the QES cliff that follows: from 1 January 2027 the Qualified Electronic Signature requirement on PDF B2B/B2C invoices ends the long grace period during which the Portuguese tax authority tolerated PDFs sent by email as legitimate "fatura eletrónica." The trade press frames the change in a single line operators repeat: a PDF without QES stops counting as an electronic invoice — it counts as a typed-out paper invoice that happens to be in PDF, which is a different legal object with different archival and SAF-T implications. The combination of CIUS-PT for B2G in 2026 and QES-on-PDF for B2B/B2C in 2027 is the year-on-year cliff PMEs describe.²

A regime operators describe by the day-to-day shape of its mechanics: ATCUD on every invoice since January 2023; QR code on every invoice since January 2023; monthly SAF-T(PT) filed by the 5th of the following month; 1 January 2026 B2G CIUS-PT XML mandatory for SMEs; 1 January 2027 QES required on PDF B2B/B2C; 2027–2028 accounting SAF-T(PT) for FY2026; AT-certified software the only legal emitter; digital archive required; contabilista certificado coordination required for filings; the cliff lands hardest on sole traders running one or two tills.^1,2

The EasyTax / Jornal Económico coverage — published as a digital-tax column on a leading Portuguese business-press title, written for the contabilista and PME-owner reader — documents the lived shape of the 2026 transition. Trade press notes that for the long tail of operators who have spent three years issuing invoices through certified software and pretending the rest of the regime "doesn't apply yet," the 2026 cliff is the year the rest of the regime applies. The chosen billing tool must already be on the AT-certified list; the CIUS-PT interface must be live whether the operator currently sends B2G invoices or not; the SAF-T(PT) cadence must be honoured monthly; and the QES-on-PDF rule that lands twelve months later forces every B2B/B2C invoice flow to be re-platformed onto a tool that can attach a qualified signature, not just print to PDF. The pain the EasyTax column makes most explicit is the cross-functional nature of the change: the certified-software vendor, the contabilista, the digital-archive provider and the QES-credential issuer all have to be coordinated by an operator whose day job is selling shoes, pouring coffee, fixing cars, or running a guesthouse — a coordination tax that is not in the price of any of the four moving parts.³

The Fiskaly coverage — published by a European fiscalization-API vendor whose Portuguese page documents the ATCUD + QR + QES + SAF-T mechanics for software houses building into the regime — records the technical-and-operational stack PMEs have inherited from a decade of incremental rule-making. Fiskaly walks through the certified-software requirement (each emitter must be on the AT's published list; each series must be communicated to obtain its ATCUD prefix; each invoice must carry the ATCUD line and the QR code; each invoice file must be private-key-signed by the certified software), the digital-archive retention duty, and the QES layer that lands on top from 1 January 2027. For the Lisbon retailer whose till prints to a Word document, the Porto café whose owner has been issuing PDFs through a free template for years, and the Algarve guesthouse whose contabilista comes around with a USB stick once a month, the regime is no longer a single milestone — it is a recurring administrative load that compounds every January, against a structured-XML rule that does not differentiate between an operator who never bought certified software and an operator whose AT-certified vendor happened to drop a single SAF-T(PT) submission during the AT clearance window.⁴

For the operator whose contabilista comes around with a USB stick once a month, the regime is no longer a single milestone — it is a recurring administrative load that compounds every January. — Portugal · Retail forum threads

02Who solves this today

Portugal-active vendors that publicly self-market to the AT-certified billing / faturação eletrónica / SAF-T(PT) / ATCUD / CIUS-PT niche on their own Portuguese-language homepages — accounting and POS platforms whose front pages name the regime as the operator promise. Each entry verified live and self-marketed in the niche on the date of writing. The Autoridade Tributária's own published list of certified software is referenced in section 01 as the regulator-published mechanic, not as a third-party solution. The list is intentionally narrow.

Moloni

Portuguese cloud invoicing and accounting platform whose homepage names the niche directly as a top-level promise — "Certificado com o nº 2860 da Autoridade Tributária," "ATCUD — Comunicação de séries à AT," and "exportando os seus documentos em formatos compatíveis com o EDI (CIUS-PT e UBL 2.1)." The route a Portuguese PME takes when they want a cloud-native billing tool that publishes AT-certification, ATCUD-series communication, and CIUS-PT export as homepage anchors rather than buried compliance notes. Reachable at moloni.pt.

moloni.pt

InvoiceXpress

Portuguese cloud-billing platform whose homepage names the niche directly as a top-level promise — "Software de Faturação GRATUITO Certificado pela AT," with "Certificado n.º 192 pela Autoridade Tributária," "Faturas eletrónicas com assinatura digital," and "Exportação do ficheiro SAF-T PT." The route a Portuguese sole trader or small operator takes when they want an AT-certified cloud invoicing tool that markets digital-signature-and-SAF-T(PT)-export as the homepage feature stack. Reachable at invoicexpress.com.

invoicexpress.com

Vendus

Portuguese cloud POS and invoicing platform whose homepage names the niche directly under its plan stack — "Software Certificado Nº 2230/AT," "Exportação automática SAF-T," and "Impressão em A4 e fatura eletrónica." The route a Portuguese retailer, café or guesthouse takes when they want an AT-certified POS that markets automatic SAF-T export and fatura-eletrónica issuance as the homepage promise. Reachable at vendus.pt.

vendus.pt

Listed providers publicly market to the Portuguese AT-certified / faturação eletrónica / SAF-T(PT) / ATCUD / CIUS-PT niche on their own homepages. Inclusion is not endorsement. Adjacent Portugal-active vendors were considered and excluded where their public homepage did not explicitly name the niche at the date of writing — Cegid (cegid.com/pt) returned HTTP 200 but the front page focused on general retail and HR management without surfacing AT-certification, faturação eletrónica, SAF-T(PT), ATCUD, CIUS-PT or the Primavera brand on the homepage proper, so it was dropped pending a re-check at the Cegid Primavera sub-site; Sage Portugal (sage.com/pt-pt) returned HTTP 403 on the date of writing and could not be verified against the named-niche-on-homepage rule, so it was dropped; Edicom (edicomgroup.com/pt) named SAF-T and faturação eletrónica B2B/B2G in passing but did not surface ATCUD or CIUS-PT on the homepage proper and was dropped per the named-niche-on-homepage rule; Tickelia, Storecove, Fonoa, Pikon and ecosio are positioned as enterprise / multi-jurisdiction tax-tech rather than Portuguese-PME-facing platforms and were dropped per the named-niche-on-homepage and SME-cohort rules. The Autoridade Tributária's own published list of certified software is the regulator's own catalogue and is referenced in section 01 as the regulator-published mechanic, not as a third-party solution provider.

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