Mandatory electronic invoicing in Spain is no longer optional. This guide walks you through everything from understanding the regulation to having your system live, with no unnecessary jargon and concrete steps tailored for SMEs.
Many business owners see electronic invoicing as just another bureaucratic requirement. In practice, when implemented well, it is one of the automations that gives back the most time and money: invoices sent automatically, payments tracked in real time, and zero paperwork to file. This guide shows you how to get there in an organised way.
1. Understand exactly what the law requires
Law 18/2022 (Crea y Crece) and its implementing regulations establish that all B2B transactions must be invoiced electronically. This covers both sending and receiving: it is not enough to send electronic invoices if you still receive paper ones. The system must be bidirectional. The regulation also requires the recipient to acknowledge receipt, and the issuer must be able to check the invoice status: received, accepted, paid or rejected.
Electronic invoicing reduces the time spent on accounts receivable management by 60 to 80 percent in SMEs that implement it correctly.
2. Know the accepted formats
Facturae 3.2.x
Spain's official XML-based format. Mandatory for invoicing Public Administrations and recommended for the private sector.
UBL 2.1
Widely adopted European standard. Compatible with most market ERPs and with the European PEPPOL network.
PEPPOL
European electronic invoice exchange network. Allows sending and receiving invoices from suppliers and clients in any EU country using a single access point.
PDF / Word
Not valid as electronic invoices under current regulations. Only acceptable as informational supplements, not as official fiscal documents.
3. Assess your current situation
Before choosing a solution, you need to know where you are starting from. There are four typical scenarios in Spanish SMEs: (a) manual invoicing from Word or Excel, which requires adopting specific software; (b) basic invoicing software, which probably just needs a module activated; (c) existing ERP without electronic invoicing module, which requires integration or upgrade; (d) ERP with included module, which just needs to be activated and digital certificates configured.
4. Choose the right solution for your volume
For SMEs with fewer than 500 annual invoices, SaaS electronic invoicing platforms from 30 to 50 euros per month are sufficient. For companies with higher volume or complex purchase and sale processes, direct ERP integration is the most efficient option: it eliminates double data entry and connects invoicing with treasury, logistics and accounting in a single system.
5. Implementation plan in 5 weeks
Week 1: audit your current process and select a solution. Week 2: register on the platform and obtain the company digital certificate, which is critical as nothing works without it. Week 3: system configuration, templates and connectors with your current ERP or software. Week 4: testing with pilot clients and suppliers in a test environment. Week 5: go live and train the admin team. This timeline is indicative; custom ERP projects may require three or four additional weeks.
6. Most common mistakes to avoid
The most common mistake is waiting until the legal deadline. The second is confusing a signed PDF with a real electronic invoice. The third is implementing only the sending module and forgetting the receiving one, as regulations require both. The fourth is not communicating the change to clients and suppliers with enough notice, which creates friction in the first months of operation.
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