These days many companies receive the request from suppliers for the " RECIPIENT CODE " or " SDI CODE " or " INTERCHANGE CODE ", each supplier uses its own terminology and / or PEC (certified e-mail) necessary for addressing to by means of the SDI (Exchange System) code of the invoices issued by the supplier.

SDI code what is it for?

Below is an example of communication from a well-known Italian provider:

"We invite you to provide us with the RECIPIENT CODE (code issued by the Revenue Agency) and / or the PEC (certified e-mail) chosen for addressing the electronic invoices issued by Fastweb via SDI (Exchange System); in the event that the RECIPIENT CODE will be provided together with a PEC, in the E-INVOICE layout we will indicate the RECIPIENT CODE as a priority. "


It is actually the INTERMEDIARY CODE (formerly known as the Univocal Code) which is issued upon request if an intermediary is delegated to manage electronic invoicing. So if you subscribe to a replacement storage service with Aruba,,, 2cSolution, infocert, etc., you will receive your INTERMEDIARY CODE - an identifier of 7 - to be communicated to your suppliers. In fact, only subjects with a transmission channel already accredited with the Exchange System to receive electronic invoices will be able to request it.

Notes : also the free replacement storage of the Revenue Agency - Invoices and Fees - allows us to have our RECIPIENT CODE :

Subscribing to a system for replacement storage is practically mandatory if you want to avoid sending and archiving our invoices manually and for free on the Revenue Agency system , to keep in mind that the deadline for archiving invoices is within the third following month on the date of the planned dispatch of the tax return of the reference year. From 2018 the storage deadline should be 31/12/2019 since the deadline for UNICO / 19 should be 30/9/2019.

The PEC is still sufficient. To check our PEC or find that of one of our customers, we can use the InfoPec service at the following address:


Yes, it must be requested from all our customers, as electronic invoicing will be mandatory between individuals starting from January 1, 2019. For individuals (without VAT number) 7 zeros will be indicated as the RECIPIENT CODE. Unfortunately, there are still many unknowns, few are really ready including Fattura24 and Smarty.


The prevalence is always the SDI recipient code . The PEC field must be entered in the XML invoice only and only if the Recipient Code value is equal to ' 0000000 '. In any case, obtaining the PEC from our customer is useful for soliciting payments at the due date or for any similar communication.

unique Aruba code where it is located

The Aruba SDI recipient code is identical for all those who have subscribed to the service with the provider. The unique code is visible by going to " Configuration> Reception data " and is KRRH6B9

private unique code

As already mentioned, if the invoice is to a private individual, what is the SDI recipient code that I must use? Simply in the invoice we will indicate the Fiscal Code of the private customer and as SDI: ' 0000000 ' (7 zeros).

Discover Invoice 24
Discover Invoice 24

Verify unique code

The search for the unique code is not necessary, as we will see later if we are not aware of the recipient's SDI and PEC, we can omit the data when issuing the electronic invoice. So when in doubt I recommend not to enter the data. However, the following table with the list 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 .

SDI Intermediaries List
Provider Unique Code
Electronic Invoice APP N92GLON
Ready Pro SN4CSRI
Is the recipient code mandatory for electronic invoicing?

No, it is not mandatory, when issuing the invoice it is sufficient to indicate the VAT number, the invoice will still arrive in the customer's tax drawer.

The addressing of electronic invoices occurs through the correct indication of the VAT number or tax code of the transferee / client. Reporting the recipient's Certified Electronic Mail (PEC) address or the recipient code are particularly useful information for delivering electronic invoices to recipients. However, in the absence of this information, the invoices are in any case deposited in the specific area of the recipients, accessible through the website of the Revenue Agency in the "Invoices and Fees" section. In fact, the Interchange System requires that the VAT number, if reported, and the tax code are regularly present in the registry and, once the formal data of the invoices have been checked, makes them available in the area dedicated to recipients based on the tax code reported in the invoices.

Is the PEC mandatory for electronic invoicing?

Also the PEC is therefore only a channel through which the ES can send the documents to the assignees, but not the only channel. The interested parties can accredit a different channel than the PEC, therefore there are no requirements for consumers in relation to the availability of a Certified Electronic Mail box. There is no obligation to request the PEC for the issue of electronic invoices to customers. Ultimately, the absence of such information does not preclude the correctness of electronic invoicing.

Electronic invoice obligation for the flat rate scheme

Interesting news coming for the flat-rate scheme from next July 1st, starting from that date the obligation of the electronic invoice will be triggered. The novelty is part of the measures against the phenomenon of tax evasion provided for by the decree on the National Recovery and Resilience Plan (PNRR).

In a few months, the rules will change for those who are on a flat-rate basis, who are currently not obliged to issue and receive electronic invoices, having the possibility of issuing invoices in paper or PDF form, except for invoices issued in favor of the PA. Let's find out below what the upcoming novelty entails and the related transitional phase.

Electronic invoice obligation for the flat rate scheme: it starts on 1 July 2022

The novelty of the electronic invoice for the flat-rate regime comes with the approval of the decree for the implementation of the PNRR by the Council of Ministers of 13 April 2022. The VAT numbers that apply the flat tax are also obliged to electronic invoice, together with the associations amateur sports and taxpayers under the benefit scheme. Individuals with fees or revenues of up to 25 thousand euros should be excluded from the obligation of electronic invoicing. VAT numbers that apply the flat tax of up to 25 thousand euros in fees or revenues should therefore continue to be exempted from the obligation.

The electronic invoice obligation for the flat-rate scheme will start from 1 July 2022 but, according to the first rumors, for the first 3 months it will be possible to issue the document by the end of the following month compared to the month in which the operations were carried out without being applied. no sanction. In summary, due to the extension of electronic invoicing, from 1 July 2022 the following categories are required to comply with the new provision:

  • subjects with a benefit regime (Article 27 paragraphs 1 and 2 of Legislative Decree 98/2011);
  • subjects on a flat-rate basis (Article 1 paragraphs from 54 to 89 of Law 190/2014);
  • amateur sports associations (articles 1 and 2 of Law 398/91).

Electronic invoice obligation for the flat-rate scheme: longer term of issue for the third quarter

For the third quarter of 2022, from 1 July to 30 September 2022, a longer issue term is envisaged for the new bonds. These subjects, in fact, will be able to issue electronic invoices by the end of the month following the one in which the operations were carried out. The deadline for issuing electronic invoices, which is normally set at 12 days from the date of the operations, is therefore temporarily extended, without the application of the sanctions pursuant to art. 6, paragraph 2, of decree no. 417/97.

However, it should be remembered that late issuance of electronic invoices entail a penalty ranging from 5% to 10% of the unregistered or undocumented fees. The sanction ranges from 250 to 2,000 € in the event that the violation committed is not relevant for the purposes of determining income.

Electronic invoice obligation for the flat-rate scheme: issuing of documents

For the issuance of electronic invoices, professionals on a flat-rate basis must have software that allows them to develop, issue and exchange invoices in XML in the Exchange System (ES). In any case, it will remain possible to use the specific section "Invoices and Fees" of the official website of the Revenue Agency. A portal that allows you to use various services for free with which it will be possible:

  • generate, transmit and store electronic invoices (to individuals and the Public Administration);
  • send some invoice data to the Revenue Agency;
  • obtain the certificates to memorize and transmit the payment data electronically and securely.

A series of services to allow electronic invoicing in a transparent, fast and secure way.


Having said that electronic invoices are correct, even in the absence of SDI or PEC, the indication of the PEC or the recipient code remains in any case appropriate and functional. A practical way to facilitate delivery. In this regard, we remind you that the recipient code is the reference of a duly accredited electronic channel, while the PEC is the certified e-mail box of the recipients, where companies can decide to receive invoices.

It is also necessary to keep electronic invoices for ten years . This is a procedure technically regulated by the law that allows the conservation of documents in digital format, maintaining the legal value of the electronic invoices themselves. The digital storage method of electronic invoices protects those affected from sanctions, as well as limiting the risks of losses and paper consumption.

Author: Loris Modena

Loris Modena


For Ind Loris Modena , owner of Arte e Informatica , he began working in the IT sector in 1989 as a system engineer in charge of the maintenance and installation of IT systems. He started programming for the web in 1997 dealing with CGI programming in PERL and then moving on to programming in PHP and JavaScript. In this period he approaches the Open source world and the management of Linux servers.

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