VeriFactu: what your invoicing software must do, and how to adapt it

VeriFactu: what your invoicing software must do, and how to adapt it

The dates in force are January and July 2027, and the old ones are still circulating. What the regulation requires from your software internally, which mode suits you, and what to do when invoices come from your own application.

· Full-stack development

Search for "verifactu" and you will find half a dozen different dates, most of them from 2026 and most of them copied from articles written before the last postponement. Let's start there, and then move on to the part almost nobody writes about: what happens when the invoices come out of your own application rather than a program you bought.

The dates that are actually in force

According to the consolidated text of Royal Decree 1007/2023, after the amendments introduced by Royal Decree 254/2025 and Royal Decree-Law 15/2025:

  • Corporate income tax payers must have their systems adapted before 1 January 2027.
  • Everyone else —self-employed workers and other personal income tax payers with business activity— before 1 July 2027.

You are not late. What you should avoid is leaving it for the last quarter, and not because of the law: because of the technical work it drags along. Changing the system you invoice with touches numbering series, templates, the shop or POS integration and the migration of your history. That is not an afternoon's work, and it cannot be tested in production on 28 December.

What it actually requires, in technical terms

The regulation does not change how you invoice. It changes what the software must do internally, and every requirement points the same way: an issued invoice must not be deletable or editable without leaving a trace.

  • One invoicing record per invoice, chained to the previous one through a hash, so that removing one breaks the chain and shows.
  • Signature and retention of those records, with traceability for any cancellation or correction.
  • A QR code on the invoice and, if the system reports to the tax authority, the "VERI*FACTU" wording.
  • An immutable history. No reprinting a three-month-old invoice with a different amount.

If you come from software, this will sound familiar: it is an append-only log with hash chaining. The difference is that here the design is not your choice, it is a requirement.

The two modes, and why the decision is a technical one

This is the part nobody explains before selling you the program.

VERI*FACTU mode: the software sends each record to the tax authority the moment the invoice is issued. In exchange, compliance is presumed and you are spared much of the retention burden and the stricter signature requirements.

Non-verifiable mode: you send nothing, but then the program must meet every integrity, retention and electronic signature requirement on its own, backed by the manufacturer's declaration of conformity.

For most small businesses the first option is cheaper to sustain, because it hands much of the retention problem to the tax authority. The second makes sense at high volume, or when there is a reason not to send data in real time. What decides is not the licence price: it is how much infrastructure you are willing to maintain.

The case no article covers: invoicing from your own application

If you issue invoices from a custom application, your online shop, an ERP someone built for you or an automated flow, there is no manufacturer who will sign a declaration of conformity for you. The system has to comply, and the system is yours.

That means concrete, bounded development work:

  • Implementing the chained invoicing record and the hash, with the format and algorithm the technical specification sets out.
  • Generating the QR code and, if you choose to report, integrating the submission to the tax authority's service, with retries and error handling: a network outage cannot leave you unable to invoice.
  • Closing off every route to modifying the history by design, including the admin one. If an update can change the amount of an issued invoice, the system does not comply even if nobody ever uses it.
  • Retaining the records and being able to export them in the required format.

It is a matter of weeks, not months, if it is done with time to spare. In December 2026, with the deadline overhead, it will be another story.

If you invoice in Word, Excel or on paper

That stops being valid, and the reason is technical: a template chains nothing and a spreadsheet can be edited without a trace, which is exactly what the rule sets out to prevent.

If you issue few invoices, the answer is not to buy an ERP. There are simple applications, some of them free, and the tax authority itself offers a basic invoicing tool. The one non-negotiable is that the manufacturer states in writing that it complies.

What to check before switching programs

  • That the manufacturer has published its declaration of conformity. If you cannot find it, ask for it in writing.
  • Which mode it implements, and whether you can change your mind later without migrating again.
  • That it exports your data. The day you want to leave, that is the difference between migrating and retyping everything.
  • If you have an online shop or a POS, that the integration is settled before you sign. That is where these projects break.

Where to start

By knowing where each invoice you issue comes from. In most small businesses they come from more than one place —the program, the shop, a stray spreadsheet for the odd cases— and that inventory, which takes a morning, is what decides whether this is changing an application or writing code.

At Mindset & Code we do that part: reviewing how you invoice today, adapting the application when the invoices come from custom software, and integrating the submission when that is the right call. If you also want to stop typing incoming invoices, we cover it in how to automate collections and in connecting your shop to your accounting.

Sources: Royal Decree 1007/2023, consolidated text in the BOE (updated 3 December 2025), fourth final provision, adaptation deadlines; Royal Decree 254/2025 and Royal Decree-Law 15/2025, which amend those deadlines; Order HAC/1177/2024, technical specifications; Spanish tax authority, invoicing software systems. Dates verified on 30 August 2026 against the consolidated text. Informative guide: it does not replace professional advice.