Accounting technology / Glossary / Italy SDI (Sistema di Interscambio)

What is the Sistema di Interscambio (SDI)?

Definition

The Sistema di Interscambio (SDI) is the Italian tax authority's platform through which businesses send electronic invoices. Since 1 January 2019, invoices between businesses established in Italy, and to Italian consumers, must be XML e-invoices sent through SDI, which checks each one and delivers it to the buyer. An invoice not sent through SDI counts as not issued.

Also calledSdIExchange SystemFatturaPAfattura elettronica

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Mandatory since: 1 January 2019
Format: XML (FatturaPA)
Model: Clearance through a central platform

How the Sistema di Interscambio works

Italy was the first EU country to require e-invoicing between businesses. The seller creates the invoice in XML, in the national FatturaPA format or a format allowed under the European standard EN 16931, and sends it to SDI directly, through the tax authority's free online tools or through an intermediary. SDI validates the file and delivers it to the address the buyer has registered, sending receipts back to the seller; rejected invoices must be corrected and re-sent. Because every invoice passes through the platform, the authority holds the data used to pre-fill VAT records. Small businesses under the flat-rate regime were brought into the mandate from 1 January 2024. Fonoa and Avalara connect international groups to SDI alongside other countries' systems.

Common questions

Who has to use SDI?+

Businesses established or identified for VAT in Italy, for invoices to other businesses and to consumers. Small businesses under the flat-rate regime have been included since 1 January 2024.

What happens if an invoice is not sent through SDI?+

It is treated as not issued for tax purposes, with the penalties that apply to a missing invoice. If SDI rejects a file, the seller must correct it and send it again.

What is FatturaPA?+

The Italian national XML format for e-invoices, first used for invoices to public bodies and now for invoices between businesses and to consumers. Formats allowed under EN 16931 are also accepted.