What is Verifactu?: Frequently Asked Questions for Software Developers

Camille Mendonça

Fiscalization Expert Spain

8 min read

Camille focuses on the Spain market as Marketing & PR Manager. With an eye for storytelling, she specializes in simplifying fiscal topics around TicketBAI, Veri*Factu, and e-invoicing, to foster transparency and compliance in an engaging way.

At fiskaly, we understand that the transition to compliance with Veri*factu raises many questions for freelancers, businesses, and especially software developers, who must comply with the technical requirements of the law before anyone else, with a deadline of July 29, 2025. During our recent webinars, we received an overwhelming number of questions about the regulation and our Verifactu API. For this reason, we’ve prepared this post compiling the most frequently asked questions and their answers. We hope you’ll find the solutions to adapt your software easily and comply with the Anti-Fraud Law.

ℹ️ The answers provided by fiskaly Iberia S.L. are for informational purposes only and are not legally binding. fiskaly Iberia S.L. is not a tax consultancy firm but a developer of tax compliance software, so the information provided is advisory in nature. In any case, any activity related to invoicing and taxation should always be consulted with a tax advisor who understands the specific implications of each regulation for individual businesses or professionals.

What is Verifactu?: Frequently Asked Questions for Software Developers

Obligation to comply with Verifactu for different types of businesses and software developers

Do simplified invoices (e.g., bar sales tickets) also need to be sent to the Tax Agency?

Does Verifactu apply to all invoicing software, such as POS systems, e-commerce platforms, ERP, and marketplaces?

Does Verifactu also apply to invoices from virtual stores and e-commerce platforms selling online services within Spain and abroad?

If a company voluntarily adheres to SII, are they exempt from complying with the Anti-Fraud Law? Can Verifactu be implemented alongside SII, even if not required?

If a former client continues using my old software (without Verifactu), can I be fined? If the client is using an outdated version of the software without a support contract, who is responsible?

Can I have clients in my software who want to adhere to Verifactu and others who do not? If I, as a developer, decide to use Verifactu mode, does that mean my clients cannot choose otherwise?

What happens if I don’t make the required software modifications by July 29, 2025?

Who manages who is subject to VeriFactu or Non-VeriFactu mode, or exemptions? Or will the taxpayer be responsible for selecting the mode?

Is Verifactu mandatory for B2C stores as well?

Do Ceuta and Melilla also need to comply with Verifactu?

Will the Tax Agency provide Verifactu software for free?

Do rental income transactions fall under Verifactu?

Verifactu technical requirements and the invoicing process

What happens if the connection is lost and the API cannot be accessed?

What does Non-Verifactu mode mean? Is it mandatory for everyone?

Will it be mandatory to include additional information on the invoice, such as a QR code?

If a company opts for Non-Verifactu mode, what is the purpose of the QR code if no communication with the tax authorities has been established and the customer cannot verify the invoice?

I have clients who are already under SII and others who are not. Will additional information need to be included on invoices (complete or simplified) indicating that the company does not display the QR code because it complies with SII?

If I need to modify details such as comments or delivery address on an invoice (i.e., non-economic data), do I also need to issue a rectified invoice?

Can the user of our software issue invoices with skipped numbering? If so, how can such skips be justified?

When is an invoice considered issued? Is it at the moment the record is saved, or does it need to be sent to be considered definitive?

Responsible Declaration for Verifactu

In TicketBAI, to certify software as compliant, a report, a video showing critical processes, etc., must be submitted. How will software compliance be certified under Verifactu?

To submit the Responsible Declaration, will there be a dedicated section in the fiskaly control panel used by our end clients?

SIGN ES: how fiskaly's Verifactu API works

Where is the XML file stored?

Does the Verifactu API always require data in JSON format, which you then convert to XML, or is it sent directly in XML? TicketBAI uses XML.

Does fiskaly also handle record storage?

Is the digital signature used by fiskaly or the taxpayer?

How will client certificates be managed? Does fiskaly handle them? Does fiskaly comply with EIDAS requirements? Do developers need to fulfill any additional requirements, even if they only facilitate the certificate for fiskaly?

Can dashboard actions be performed via API?

Once Verifactu API calls are implemented in our software, is it necessary to certify the software with the AEAT?

Where can we find the documentation for the information that must be sent in the API JSON for each invoice? For example, invoices with complex details, multiple VAT types, equivalence surcharge, early payment discounts, withholdings, etc.?

Can the Verifactu API be integrated with Filemaker?

In the event of an AEAT information request, would fiskaly directly provide the information to the AEAT?

What is the cost of integrating fiskaly's Verifactu API?

Can fiskaly's SIGN ES API be used to comply with both Verifactu and TicketBAI simultaneously?

Interested? Contact our team