How to adapt your billing software to VeriFactu and the Create and Grow Law

In this article you will analyze, step by step, how to prepare your billing software and your ERP to comply with VeriFactu and with the standard known as Create and Grow Law for SMEs, what technical and organizational implications the transition has, and why the existence of an anti-fraud law and measures such as mandatory timekeeping are relevant to the fiscal and operational health of companies.

Executive Summary

• Objective: To guide technical managers and SME managers in adapting their billing systems to the new legal and technical framework (VeriFactu and the Crea y Crece Law).
• Expected outcome: A work plan with technical priorities, functional changes, testing, and deployment recommendations.

Essential legal and technical context

What is VeriFactu

VeriFactu designates the set of technical and operational requirements defined for the Billing Information Systems (SIF) with the aim of ensuring the integrity, traceability, and authenticity of invoices issued and received by companies and self-employed individuals in Spain.

The Tax Agency maintains official technical documentation, tools, and guides on VeriFactu and SIFs, including a consultation and assistance application for technical compliance and secure record sharing.

What is the Create and Grow Law?

The Create and Grow Law promotes the digitalization of commercial relations between companies and self-employed individuals by establishing the obligation to issue and, in some cases, receive invoices in electronic format, with staggered deadlines based on volume and specific obligations designed to promote liquidity and reduce late payments in SMEs.

The Anti-Fraud Law complements these developments by imposing requirements for the traceability and recording of invoices and billing programs to reduce tax fraud; VeriFactu stems directly from this regulatory commitment to ensure technical controls over SIFs.

Mandatory signing and its relationship with billing

Mandatory time recording (clocking in) is part of the regulatory package seeking greater traceability in business management and the use of working time. Although it is a labor regulation, it shares the transparency and record-keeping principles underpinning the Anti-Fraud Law and verifiable invoicing systems.

Why an anti-fraud law and the digitalization of invoices matter

• Fiscal transparency and a smaller black economy: The integration of technical standards reduces opportunities for modifying accounting records and facilitates the detection of inconsistencies by management.
• Improvements in treasury and reduction of delinquencyThe obligation to invoice electronically between companies reduces administrative time and facilitates reconciliation and collection processes, a central objective of the Create and Grow Law for SMEs.
• Legal certainty and automationSystems that guarantee integrity and signature, support legal processes, and automate tax compliance, avoiding penalties for failure to maintain or alter records.
• Culture of compliance: : Timekeeping, electronic invoicing, and technical verification promote internal controls and business practices geared toward traceability and internal auditing.

Preliminary diagnosis and technical checklist before starting

Before modifying code or purchasing services, perform a self-diagnosis of your current situation. Evaluate these elements and prioritize them based on risk and effort.

• System inventory: list of modules, APIs, RFCs, and invoice issuance points.
• Current formats: document types (XML, PDF, EDI), data schemas and metadata.
• Third-party integrations: banks, payment platforms, marketplaces, external accounting software.
• Non-functional requirements: availability, encryption in transit and at rest, event traceability.
• Governance and change control: who signs off on changes, deployment procedures, rollback.
• Conservation and access: retention policies and how to respond to requests from the AEAT.

Classify each element as Critical, Important, Cheap and prepare a roadmap with milestones and those responsible.

Concrete steps to adapt your billing software

1. Understand the functional and technical requirements

• Incorporate the concept of verifiable billing record: Each invoice must include metadata that allows for traceability and integrity verification according to the criteria of the AEAT regulations and guidelines.
• Implement digital signatures or seals and retain information on relevant events (issuance, modification, dispatch, acceptance) with a time stamp when applicable.
• Ensure that the invoice history cannot be altered, or if changes occur, clearly record the versions and the reason for the change.

Practical technical reference: Review the AEAT Guide on SIF and VeriFactu to learn about the record specifications and the recommended testing plan.

2. System architecture and design

• Design an abstraction layer for billing that separates: document generation, persistence, transport to third parties (customers, administrations), and audit logs.
• Add a traceability service that records immutable (append-only) events in a database optimized for forensic queries.
• Evaluate storage in open and standardized formats (e.g., XML JSON with official schemas) to facilitate interoperability with suppliers and the AEAT.

3. Changes in the issuance and reception of invoices

• Issuance: Include the required metadata (unique identifiers, hashes, date and time of issue, billing software reference and version) in the invoice and generate a digital integrity check.
• Receiving: Validates the integrity and origin of incoming invoices; implements automatic filters to discard invoices with invalid signatures or inconsistent metadata.
• Connectors: Incorporates adapters to consume official APIs or go through authorized intermediaries when required.

4. Integration with the AEAT and third-party tools

• Test interoperability with the free app or with APIs published by the AEAT to consult records and validate submissions.
• Consider market solutions (APIs from integrators such as Wolters Kluwer, Conectia, or SaaS providers that already offer adaptations to VeriFactu) to shorten compliance time and outsource maintenance of the regulatory layer.

5. Data security and compliance

• Encrypt sensitive data at rest and in transit; enforce role-based access control and detailed auditing of access and changes.
• Implement immutable backup mechanisms and periodically verify the ability to restore logs with intact integrity.
• Maintain an inventory of dependencies and security patches to prevent vulnerabilities that could allow registry manipulation.

6. Testing, validation and deployment

• It defines a battery of functional and integration tests to cover: issuance, modification, cancellation, record export, and consultation with the AEAT.
• Perform load testing to validate scalability and latency when generating or sending large volumes of invoices.
• Implement a staging environment that replicates the interaction with the AEAT or integrators and runs end-to-end tests before production.

Organizational requirements and operational processes

• Document and communicate changes to the accounting and sales teams; train managers in issuance, validation, and maintenance procedures.
• Review contracts with clients and suppliers to agree on formats and channels for exchanging electronic invoices.
• Establish internal SLAs for issuing, responding to incidents, and submitting records for tax inspections.
• Defines legal and technical managers responsible for responding to AEAT inquiries regarding the integrity of the SIFs.

Deployment Options: Develop vs. Integrate

Develop internally

• Advantages: total control and business-specific adaptations.
• Risks: development and maintenance costs, need for legal and technological expertise to maintain compliance.
• Recommendation: viable for companies with mature technical teams and high turnover.

Integrate market solutions or intermediaries

• Advantages: reduced adaptation time, regulatory updates managed by the supplier.
• Risks: supplier dependence and recurring costs.
• Recommendation: A good option for SMEs and companies that prefer to outsource complexity; evaluate providers that offer certified or compatible VeriFactu connectors.

Practical examples and use cases

• Case 1: Small company with legacy ERP: Add a SIF module that exports records in the required format, implements signatures, and sends summaries to an intermediary who manages submission to the AEAT.
• Accounting SaaS Case 2: Create endpoints that expose immutable billing history and add an interoperability testing plan with the AEAT (Spanish Tax Agency); offer clients self-adaptation tools.
• Case 3: Marketplace platform: centralize issuance and validation on the platform; define contractual responsibilities with sellers and buyers to maintain traceability of transactions and reconciliations.

Best practices and final checklist for launch

• Have an immutable backup with retention in accordance with regulations.
• Have immutable and auditable logs that allow the audit trail to be reconstructed.
• Maintain a software version policy visible on each invoice issued.
• Generate hashes and signatures that allow the integrity of each document to be verified.
• Have automated tests that cover issue, modification, and cancellation flows.
• Establish a communication plan for customers and suppliers regarding the change and adaptation deadlines.

Impact on SMEs and strategic recommendations

• For many SMEs, the law creates and grows for SMEs It has a double effect: it improves the negotiating position with large clients and requires a technological leap that, in the short term, generates costs but in the medium term reduces errors and improves collections.
• Strategic recommendation: Prioritize solutions that minimize operational friction (plugins for existing ERPs, certified integrators) and plan resources for migration and internal training.

Conclusion and recommended immediate steps

1. Perform a technical and organizational self-diagnosis and classify risks.
2. Identify whether your software can be adapted via modules or if you need an authorized integrator.
3. Implement a traceability and integrity testing service following AEAT guidelines.
4. Test integrations with the official tool or certified vendors before deploying to production.
5. Communicate the change to customers and suppliers and train the internal team on the new procedures.

Adaptation to VeriFactu and the Create and Grow Law is not only a legal requirement, it is an opportunity to improve internal controls, protect the business against fraud and modernize collection and reconciliation processes that directly impact liquidity and competitiveness.