AEAT public platform (SPFE) for free invoice exchange and universal repository of faithful copies; must be available at least 2 months before the first compliance deadline (per Royal Decree 238/2026). The SPFE works exclusively with UBL syntax aligned to EN 16931:2026 (UBL 2.5). Private platforms are permitted but must interconnect with all market platforms (no vendor lock-in) and must deposit a faithful copy (copia fiel) in the SPFE simultaneously with issuance, flagged via the CopyIndicator field. Each invoice carries a unique code (issuer NIF, series and number, and issue date) enabling automatic deduplication. Recipients must report rejection (silence counts as acceptance), the full payment date and the payment due date. Connectivity is via synchronous web services with electronic certificate authentication; retrieving invoices or statuses requires a power of attorney (apoderamiento) registered with AEAT. Senders must validate against the published XSD schemas and Schematron rules, as no production validation service will be offered. Structured file formats required; PDF and Excel are not accepted as electronic invoices.