Instant payments have had a decade of investment and attention. The work that follows a payment for the smallest businesses, the certified invoice, the VAT return, the social security declaration and the audit-ready record, has had far less. In Portugal that layer is unusually formal: invoicing software has to be certified by the tax authority, and the rules that govern it are prescribed in detail.
FIZ is a Lisbon-based tax and invoicing platform built for Portugal’s self-employed. It operates under tax authority certification number 3041, says it has more than 20,000 users, files taxes automatically for freelancers, and covers fines of up to 1,500 euros per filing when it gets one wrong. Petr Kutis, its co-founder, answered The Fintech Times‘ questions in writing. He argues that Portugal is not an outlier but an early adopter of where European compliance is heading, and that a company which underwrites its own filings has to be built like a payment system.
Four systems, four calendars
Asked what the compliance burden looks like across a year, Kutis starts with the mismatch between the job and the obligation. “A freelancer in Portugal is not asked to be a freelancer. They are asked to run a small finance department.” Every payment must be met with a certified invoice at the moment it arrives. VAT is filed quarterly. Social security runs on its own clock, with quarterly income declarations, monthly contributions and a contribution base recalculated from what was declared. Income tax arrives once a year with its own annex, and around all of it sit withholding at source, the SAF-T submission and years of records.
“The difficulty is not any single obligation. It is that four systems run on four calendars, four definitions of income and four interfaces, and a mistake in one flows silently into the rest.” Even the rates depend on where the freelancer lives: 23 per cent on the mainland, 22 in Madeira, 16 in the Azores. “Almost nobody we help was trying to avoid anything. They set one regime wrongly and found out months later, when the penalty arrived.”
Certification as infrastructure
Certified invoicing is a legal requirement in Portugal, and Kutis says that changes what financial software is. “Certification means the invoice ledger stops being a feature you can iterate on and becomes infrastructure you are accountable for.” Numbering sequences, the signature chain, the SAF-T export and the precise ways a document may be corrected are all prescribed and audited, and material changes go back through the tax authority.
He sees two effects. Certification raises the floor, so a generic invoicing tool cannot enter the market and the market is smaller and, in his words, considerably more serious. It also puts something rare at the centre of the product: a legally trustworthy, structured record of everything a person has earned. “This is the part outsiders miss. Almost everywhere else, financial software infers your income from a bank feed. In Portugal it knows. Certification is the price of entry, and the reason everything downstream, automated filing, guarantees, advice worth trusting, can exist at all.”
Why, then, was this layer left behind while payments were modernised? Kutis’s answer is that the two problems are opposites. “Payments modernised because the problem is universal and the buyer can pay for it. Compliance is the opposite on both counts.” Compliance is national and even regional, thresholds and forms are revised every year, and the person carrying the complexity is the smallest customer in the market, with no budget and no finance function. “Payments solved the easy part: the money moves in a second, and the consequences of it moving take a year.” The gap, he says, is why software in this market can no longer simply record; it has to advise on what a payment means for VAT, contributions and the year, and be right.
What trusted automated filing needs
Two things have to be true before a tax return can be filed automatically and trusted by the user and the authority at once. The first is that the source of truth is the certified document rather than an inference. “A return assembled from bank movements is a guess; a return derived from certified invoices is a derivation, and every figure traces back to a document.” The path from record to declaration has to be deterministic and replayable: the same inputs produce the same return, every rule change is versioned, and any filing can be explained a year later.
The second is reconciliation, which he calls the real frontier: matching bank transactions continuously against invoices and statements so that the picture is complete rather than merely certified. “That is the layer the world is waiting for, and Portugal is simply the place where it can be built first. Within a decade it will be ordinary everywhere.” He adds that the vendor should carry the risk, and FIZ covers penalties of up to 1,500 euros per filing.
Portugal went first
The Fintech Times put it to Kutis that Portugal certifies invoicing software while other European markets do not, or do so differently, and asked what that fragmentation means for a company trying to serve microbusinesses across Europe. He rejects the framing. “I would question the premise. Portugal is not the odd one out. Portugal went first.”
By his account Portugal applied the OECD’s SAF-T standard nationally in 2008 and began certifying invoicing software in 2010, which looked eccentric at the time. He now points to Spain’s Veri*factu, which requires certified billing systems from 2027, to Italy’s clearance invoicing, to Poland’s KSeF and Belgium’s mandate in 2026, to France completing its rollout in 2027, and to the EU’s ViDA package pointing the whole union in one direction by 2030. “So the fragmentation is real, but it is temporary. It is a convergence in progress, and it is converging on the model we already live inside.”
That, he argues, changes what building in Lisbon means. “We are not adapting to a strange local rule. We are operating in the future of European compliance about a decade early, and the hard part, the part that does not travel, is the part we have already built.”
Answerable for other people’s money
Standing behind a filing financially is unusual for a fintech. Asked what taking on that risk changes about how the product is built and tested, Kutis reframes the company. “Because we are not really a software company. We are answerable for other people’s money, for more than 20,000 people who cannot personally check what we file on their behalf.”
“A defect in most products costs someone time. A defect in ours costs a person money they may never recover, and it arrives as a letter from the state months later. Once you accept that, ‘probably correct’ stops being a category.” The filing path is engineered and tested like a payment system: fixed test suites over real historical cases, past periods replayed whenever a rule changes, FIZ’s figures reconciled against what the authority accepted, and a rule that anything ambiguous stops and asks rather than guesses. It also decides what the company will not ship. “What is acceptable as guidance is unacceptable as a filing.”
He does not put all of it down to architecture. Work of this kind, he says, needs people who understand that they are serving someone’s livelihood, and that care cannot be outsourced.
What he wants from regulators
Asked what European regulators and tax authorities should do differently over the next few years, Kutis leads with the relationship. “Above all, be more open to working with us.” Tax authorities and companies like FIZ want the same outcome, more people correctly registered, correctly filed and paying on time, and a compliant customer stays in business and stays a customer. “We are not on opposite sides of the table, yet the relationship is still built more on inspection than on cooperation.”
His concrete asks are open, documented APIs and public sandboxes as a matter of course; machine-readable rules and versioned specifications, so that compliance can be proven continuously rather than certified once; and a stable calendar, because change announced late is the single largest source of error he sees. His last request is a change of category. “Treat the one-person business as its own category rather than a shrunk-down company. Most of their obligations were inherited from corporate law and then simplified, which is why they still quietly assume an accountant.”
On Kutis’s own timeline the next test of his convergence argument is Spain, where Veri*factu requires certified billing systems from 2027.
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