Confirm your applicability date: corporate taxpayers must comply from 1 January 2027; self-employed individuals with economic activity from 1 July 2027 — earlier 2026 deadlines referenced in older documentation have been postponed by one year.
Register your billing software or access point with AEAT and obtain the technical specifications for the Veri*factu submission web service from the AEAT developer portal.
For each invoice, generate a chaining hash (huella) by applying SHA-256 to specified fields of the previous invoice in the series, producing a tamper-evident chain; include this hash and the previous invoice's timestamp in the current record.
Submit invoice records to AEAT in real-time or in batches using the AEAT web service for billing records (Article 15) or verifiable invoice records (Article 16.1); real-time submission posts each record immediately after issuance.
Embed a QR code on every invoice visualization that encodes the AEAT verification URL; also print the phrase confirming the invoice is verifiable on the AEAT website.
Test all flows in the AEAT pre-production sandbox environment before enabling production submission.
Known gotchas
The January 2026 and July 2026 deadlines cited in 2024 documentation have been pushed back by one year — plan for January 2027 and July 2027 respectively; verify against the current AEAT gazette before setting your go-live date.
The chaining hash must reference the immediately previous invoice in the series, not just any prior invoice — a gap or incorrect pointer will cause the chain to fail AEAT validation.
Veri*factu and SII (Suministro Inmediato de Información) are separate obligations; large businesses already on SII have specific Veri*factu transitional rules — confirm which regime applies to each taxpayer.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp