Verifactu for custom invoicing software
Your invoicing program has been running for years and you don't want to replace it. From 2027 it has to produce Verifactu records. I adapt it, or if you'd rather switch, I migrate your data. Either way you know beforehand what can be done and what it costs.
The deadlines
Companies subject to Corporate Income Tax (Impuesto sobre Sociedades).
All other businesses and self-employed professionals.
Source: Real Decreto 1007/2023, as amended by Real Decreto-ley 15/2025 (BOE 3 December 2025).
Who this is for
Custom ERP or in-house program
Written by a former employee or by a company that no longer exists, and the whole business depends on it.
Access, Excel or FileMaker
Invoices built from templates or an old database.
Older PHP applications
Laravel, CakePHP, CodeIgniter or plain PHP, often on a version that no longer gets updates.
Online shops
WooCommerce or PrestaShop with custom code where a standard module doesn't fit.
Not for you if you already want to move to an off-the-shelf program and your data fits a simple import. Then you don't need a developer.
Three ways forward
1. Adapt your program
Your program stays and I add what Verifactu requires. Your team keeps working the way it always has.
2. Migrate to contix
If the old program isn't worth keeping, I move customers, products and invoices to contix, the invoicing program I develop myself.
3. Modernise while you're at it
If the code has to be opened anyway: upgrade PHP or Laravel, rewrite an abandoned framework, move servers and email.
How I work
Review
I look at your program, your data and how you invoice. You get what can be adapted, what can't, which path makes sense, and a fixed price.
Development
Adaptation or migration, as agreed.
Testing against the AEAT
Everything is tested in the Spanish Tax Agency's test environment before a single real invoice goes out.
Go-live
Switch-over on an agreed date, with the old system still available as a way back.
What Verifactu requires from the program
- An invoicing record for every invoice issued or cancelled.
- A fingerprint (SHA-256 hash) of each record, chained to the previous one.
- A QR code and the «VERI*FACTU» legend on the invoice.
- Sending the records to the AEAT, or storing them signed in the «No VERI*FACTU» mode.
- The responsible declaration for the software (art. 13 RD 1007/2023).
Technical summary of RD 1007/2023 and Orden HAC/1177/2024. The binding text is the one published in the BOE.
Why me
I'm an engineer and have been developing software for more than 30 years, based in Madrid. I build contix, my own invoicing program, with records, hash chain, QR and submission working against the AEAT test environment. What I do in your program, I have already built in mine.
Frequently asked questions
Do I have to change programs because of Verifactu?
Not necessarily. A custom program can be adapted if its code and data allow it. We find out in the review.
Can an Excel sheet be adapted?
A spreadsheet on its own doesn't create chained records or send them. It usually makes more sense to migrate the data to a program that does.
Who signs the responsible declaration?
The declaration is signed by the producer of the system. Who that is in your case depends on who developed and maintains the program. We clarify it in the review, together with your accountant.
What is the «No VERI*FACTU» mode?
The records aren't sent immediately but stored signed in the system itself. Which mode suits you is your decision, together with your accountant. The program can support either.
What happens to older invoices?
Technically they remain available in the old system, or we migrate them if you switch programs. What the rules require for them, please confirm with your accountant.
How much does it cost?
It depends on the program. That's why I start with a review and give you a fixed price before any work begins.
Do you work with my accountant?
Yes. I take care of the software. Tax decisions are made by you and your accountant.
Tell me which program you have
I'll take a look and give you a fixed price.
Martin Schenk S.L. develops and adapts software. It does not provide tax or legal advice. Which obligations apply to you and which mode you choose is decided by you with your accountant or tax advisor. The legal references on this page are a summary without guarantee; the binding text is the one published in the BOE.