Electronic invoicing is a process that has revolutionized the way companies and professionals manage their financial transactions. At the heart of this process is the Interchange System (SDI), a mandatory channel for the transmission of electronic invoices in Italy. This article will explore in detail the role of the SDI code in electronic invoicing, how to find it, and how to use it to simplify and automate invoice management.
The electronic invoicing is a system for issuing and managing invoices in digital format, which simplifies and automates the invoicing process between companies. It replaces traditional paper invoicing, eliminating the need to print, send, and store invoices on paper, and standardizing the management of invoicing between companies and public administration through the XML format.
The SDI, acronym for Sistema di Interscambio, is therefore a fundamental tool for managing electronic invoicing in Italy. It is a telematic platform that allows the sending and receiving of electronic invoices between companies and the Public Administration. Its main objective is to simplify and automate the process of issuing and receiving invoices, making it more efficient and transparent, standardizing the format of electronic invoices and the methods of sending, receiving, managing, and archiving.
But what is the SDI actually for? First of all, it allows businesses to save time and energy in managing their invoices. Thanks to the dematerialization of documents, it is no longer necessary to print and send paper invoices, nor to archive them manually. The use of the XML format (eXtensible Markup Language) and the standardization of invoices greatly simplifies the import of incoming and outgoing invoices into management systems, avoiding errors. Moreover, the SDI ensures the immediate sending and receiving of invoices, preventing delays or errors in delivery.
The SDI represents an important tool to combat tax evasion. Thanks to the traceability of financial flows and the digital archiving of invoices, tax authorities have greater control over the economic transactions of businesses. This way, it is possible to identify any fraud or irregularities in corporate accounting.
Finally, the SDI represents an important step towards the digitalization of the country’s system. Its introduction has allowed for the elimination of many bureaucratic processes related to the management of paper invoices, simplifying the relationship between businesses and the Public Administration. In summary, the SDI is a fundamental tool for managing electronic invoicing in Italy. Thanks to its introduction, businesses can save time and energy in managing their invoices, combat tax evasion, and contribute to the digitalization of the country’s system.
An electronic invoice is a digital document that contains all the information related to a commercial transaction between two parties: the seller and the buyer. It must be generated in a structured format, defined at the national or international level, which allows interoperability between different invoice management systems. The electronic invoice contains the same information found on a paper invoice: the identification of the seller and the buyer, the description of the goods or services provided, the unit price, the applicable VAT rate, the total amount of the transaction, and the date of issue.
However, unlike the paper invoice, the electronic one has some peculiar characteristics: it is generated in digital format, digitally signed by the seller (through a digital certificate), and sent to the buyer via telematic channels (such as email or web portals). The electronic invoice has numerous advantages over traditional paper: it allows for greater speed in the issuance, receipt, and processing of invoices, reduces the costs of managing and storing accounting documents, and ensures greater security and integrity of data.
It is actually the INTERMEDIARY CODE (formerly known as Unique Code) that is issued upon request in case an intermediary is delegated to manage electronic invoicing. Therefore, if you subscribe to a substitute storage service with Aruba, Register.it, keliweb.it, 2cSolution, infocert, etc., you will receive your INTERMEDIARY CODE - a 7-character alphanumeric identifier - to communicate to your suppliers. In fact, only those who hold an accredited transmission channel with the Exchange System to receive electronic invoices can request it.
Note: even the free substitute storage of the Revenue Agency - Invoices and Payments - allows us to have our own RECIPIENT CODE more details here: https://bit.ly/2Cir4Vq
Subscribing to a system for substitute storage is practically mandatory if you want to avoid sending and archiving our invoices manually and for free on the Revenue Agency's system, keeping in mind that the deadline for archiving invoices is within the third month following the date of the expected submission of the income tax return for the reference year.
The PEC is still sufficient. To verify our PEC or find that of a client, we can use the InfoPec service at the following address: https://www.inipec.gov.it/cerca-pec
Yes, it is required from all our customers, as electronic invoicing will be mandatory between private individuals starting from January 1, 2019. For private individuals (without VAT number), 7 zeros will be indicated as the DESTINATION CODE. Unfortunately, there are still many uncertainties, and few are truly ready, including Fattura24 and Smarty.
Below is an example of communication from a well-known Italian provider:
“We invite you to provide us with the DESTINATION CODE (code issued by the Revenue Agency) and/or the PEC (certified electronic mail) chosen for the addressing via SDI (Interchange System) of the electronic invoices issued by Fastweb; in the event that the DESTINATION CODE is provided along with a PEC, we will prioritize the DESTINATION CODE in the electronic invoice layout.”
The prevalence is always of the recipient code SDI. The PEC field should be included in the XML invoice only and only if the value of the Recipient Code is equal to ‘0000000’. However, obtaining the PEC from our client is useful for reminding them of payment deadlines or for any similar communication.
As already mentioned, if the invoice is to a private individual, what is the SDI recipient code that I should use? Simply, in the invoice, we will indicate the Tax Code of the private customer and as SDI: ‘0000000’ (7 zeros).
For electronic invoices issued to foreign entities residing in the EU, the recipient code is XXXXXXX (seven times X), while for non-EU entities, the code OO99999999999 (two uppercase letters O, eleven 9s) must be entered. It is also necessary to send a courtesy copy in PDF format to foreign entities, as they do not have the option to receive it in their own tax drawer.
Our modules for PrestaShop allow your B2B customers to enter the electronic invoicing SDI code.
The search for the unique SDI code (or recipient code for electronic invoicing) is not necessary, as we will see later, if we are not aware of the SDI and the PEC of the recipient, we can omit the data when issuing the electronic invoice. Therefore, when in doubt, I recommend not to include the data. However, the following table with the list of intermediaries may be useful. In fact, it is a unique code for many services; if you are an Aruba customer, your code will always be KRRH6B9, while for TeamSystem customers, the unique code is M5UXCR1.
The SDI recipient code of Aruba is the same for all those who have subscribed to the service with the provider. The unique code can be found by going to "Configuration > Reception Data" and is KRRH6B9
Below are the main SDI codes of the most common intermediaries
| Provider | Unique Code |
| ARUBA | KRRH6B9 |
| PASSEPARTOUT | 5RUO82D |
| TEAMSYSTEM | M5UXCR1 |
| ZUCCHETTI | SUBM70N |
| REGISTER | PZIJH2V |
| BUFFETTI | BA6ET11 |
| INFOCERT | XL13LG4 |
| FATTURA24 | SZLUBAI |
| Electronic Invoice APP | N92GLON |
| Ready Pro | SN4CSRI |
No, it is not mandatory; when issuing the invoice, it is sufficient to indicate the VAT number, and the invoice will still arrive in the customer's tax drawer.
The addressing of electronic invoices is done through the correct indication of the VAT number or the tax code of the buyer/client. Providing the Certified Email (PEC) address of the recipient or the recipient code is particularly useful information for delivering electronic invoices to the recipients. However, in the absence of this information, invoices are still deposited in the appropriate area for recipients, accessible through the Revenue Agency's website in the "Invoices and Payments" section. The Exchange System requires that the VAT number, if provided, and the tax code, are regularly present in the registry, and once the formal data of the invoices are checked, they are made available in the area dedicated to recipients based on the tax code indicated in the invoices.
The PEC is therefore just a channel through which the SDI can send documents to the recipients, but it is not the only channel. Interested parties can register a different channel than the PEC, so there are no requirements for consumers regarding the availability of a Certified Email inbox. There is no obligation to request the PEC for the issuance of electronic invoices to customers, just as we can omit the unique electronic invoice code SDI. Ultimately, the absence of such information does not compromise the correctness of electronic invoicing. Therefore, the SDI code or PEC is just a courtesy data.
If you make a mistake when entering the SDI or the PEC, or if your client provides incorrect ones, the invoice will not be visible on the software or web service used by the client, but it can still be retrieved in the "invoices and payments" section of the Revenue Agency's website.
Even in case of error, the invoice can always arrive in the management system; on the Revenue Agency's website, in the "Invoices and Payments" section, it is possible to indicate the prevailing SDI code, in this way it will be associated with the VAT number and every issued invoice will always be delivered to the invoicing software in use.
The VAT number is the most important data of the invoice, so it is possible to receive an electronic invoice from another entity in your tax drawer if our VAT number has been indicated on it. In this case, we just need to reject it.
From July 1, 2022, the obligation of electronic invoicing also applies to flat-rate and minimum regimes that have exceeded 25,000 euros. This measure is part of the measures against tax evasion provided for by the decree on the National Recovery and Resilience Plan (PNRR). The obligation will apply to all flat-rate and minimum regimes starting from January 1, 2024.
Currently, all VAT numbers are required to issue electronic invoices, with the exception of:
It is advisable to consult your accountant, as often the adoption of electronic invoicing by those for whom it is not mandatory provides interesting tax advantages and not just greater ease of accounting management.
Electronic invoicing in Italy has been in place for several years, this is the third revision of the article (updated March 2023), and the European Union is also preparing to adopt a European electronic invoicing. It will start in 2028 with the obligation to report intra-EU B2B transactions. The journey will be very long, but for once Italy, aided by the fight against tax evasion, is ahead of the curve and will be used as a model for the European system.
As we have seen, the exchange system offers countless advantages, greatly simplifying the management of documents at the software level, especially among different management systems. In the past, each system used its own format and logic for data management, interpreting national tax regulations as best as possible. Today, thanks to the XML format and standardization, electronic invoices can be managed by any IT system, and especially the management of supplier invoices with electronic invoicing requires less time and is subject to fewer errors. In the past, there was no other way than to manually enter supplier invoices into one's management system, which incurred significant costs for businesses. Undoubtedly, electronic invoicing and SDI have renewed the sector, and today, four years after the obligation, especially for freelancers and micro-enterprises, things have changed a lot. The entire sector has been renewed, and invoicing programs are now much more standardized and economical. The archiving services for electronic invoices have become increasingly comprehensive, and today they are fully-fledged management systems with an annual cost of just a few dozen euros. Many VAT numbers managed invoices in a disorganized manner, often using unsuitable programs like Excel. Electronic invoicing and SDI have imposed the adoption of standardized and correct programs and procedures, which is the main advantage of the exchange system.
Author: Loris Modena
For Ind Loris Modena, owner of Arte e Informatica, started working in the IT sector in 1989 as a system administrator responsible for the maintenance and installation of computer systems. He began programming for the web in 1997, focusing on CGI programming in PERL and later transitioning to programming in PHP and JavaScript. During this time, he became familiar with the Open Source world and the management of Linux servers.
