Self-invoices and VAT integration for reverse charge (TD17, TD18, TD19) in SamBooks

When you buy goods or services from a supplier who doesn't apply Italian VAT — a foreign supplier, or a domestic transaction subject to the reverse charge mechanism — you, the buyer, have to self-assess the tax. Here's how SamBooks detects it, how you generate the right document (TD16, TD17, TD18 or TD19), and when the accounting entry is actually created.

What it's for

Reverse charge shifts the obligation to self-assess VAT from the supplier to the buyer: the supplier invoices without tax, and you have to "integrate" it — calculate it and record it, as both a debit and a credit at the same time. In SamBooks this happens by generating a self-invoice or integration document, always starting from a purchase invoice already on file.

The document type changes depending on the case:

• TD16 — domestic reverse charge: an Italian supplier invoicing without VAT for a transaction subject to reverse charge (e.g. construction subcontracting, cleaning/demolition services, mobile phones, scrap metal).
• TD17 — purchase of services from a foreign supplier, EU or non-EU: the default type proposed for any non-Italian supplier.
• TD18 — purchase of intra-EU goods from an EU supplier.
• TD19 — goods already in Italy purchased from a non-established foreign party.

SamBooks detects on its own when a self-invoice is needed and proposes the most likely type; TD18 and TD19, along with the rarer TD20 (regularization) and TD21 (plafond overrun) cases, must be chosen manually, because they can't be inferred from the received invoice's data alone.

This guide only covers the self-invoice mechanism. For the rest of the purchase cycle — how the source invoice arrives and gets recorded — see Recording a supplier invoice; for the full catalog of electronic-invoice TipoDocumento codes see Electronic invoice document types.

Before you start

• You need a purchase invoice that's already confirmed, posted or paid — not a draft: the self-invoice can't be generated until it's confirmed.
• Manager or Administrative role; a Viewer can only look.
• If every nature code declared on the invoice is out of scope for Italian VAT (N1, N2 or N2.1), no self-invoice is needed at all: there's no Italian tax to self-assess, and SamBooks proposes nothing. Don't mistake N2.2 for one of these: it's the code SamBooks itself writes on the zero-tax lines of a foreign invoice, and it does not switch the self-invoice off.

Step by step

1. Recognize when it's needed: the «Self-invoice» card

Open the purchase invoice's detail page. If the document requires reverse charge, a card titled "Self-invoice (reverse charge …)" appears above the tabs, where in place of the ellipsis you read the name of the proposed type (for instance "Self-invoice for foreign services"). Under the heading sits the detection reason, spelled out: "Foreign supplier (DE): reverse charge under art. 17 para. 2 of DPR 633/72 → self-invoice/integration TD17 (use TD18 if this is an intra-EU purchase of goods).", or, for an Italian supplier with an N6 nature line, "Domestic reverse charge (nature N6.3) under art. 17 paras. 5-6 of DPR 633/72 → integration TD16." If the card doesn't appear, the invoice doesn't require a self-invoice.

2. Click "Generate self-invoice" and check the document type

A preview dialog opens. The Document type field starts from SamBooks's suggestion — TD16 for an Italian supplier, TD17 for a foreign one — but it's a dropdown: change it if your case is different. The entries carry the name of the operation, not the code:

• "Intra-EU goods purchase integration" (TD18), if the EU supplier sold you goods, not services;
• "Self-invoice for art. 17 c. 2 goods" (TD19), for goods already in Italy bought from a non-established foreign party (goods imported from a non-EU supplier, instead, pay VAT at customs through the customs bill, not through a self-invoice);
• "Self-invoice for regularization" (TD20) and "Self-invoice for plafond overrun" (TD21), for the rarer cases.

3. Check the rate, document date and amounts in the preview

Below the document type, the dialog shows VAT rate % — the box is empty and shows the rate already on the received document in grey: leave it empty to keep that rate, or type a number to override it — and Document date, which you can also leave blank: if you leave it blank, SamBooks works out on its own the date prescribed for that type of transaction (the Italian Tax Agency's guidance wants a different one depending on the case: the receipt date for intra-EU service integrations, the transaction date for extra-EU self-invoices) and shows it as a reference below the field. The card underneath summarizes Supplier, Taxable amount and Integrated VAT, recalculated live every time you change the type or the rate.

4. Generate a draft only, or generate and send to SDI

Two buttons side by side — both stay greyed out until the preview has finished calculating:

• "Generate draft only" — creates the document as a Draft, without transmitting it. You can review it before deciding what to do with it.
• "Generate and send to SDI" — generates and transmits to SDI in one step, irreversible. It's only enabled for types that actually get transmitted — TD17, TD18, TD19, TD20, TD21. TD16 is never sent to SDI, because it's a purely internal integration: below the disabled button you'll read "This document type isn't transmitted to SDI: you can only generate the draft."

Either way, a note reminds you the transaction is VAT-neutral: the integrated tax is posted as both a debit and a credit for the same amount.

5. For TD16, issue the self-invoice separately

Once you've generated a TD16 draft, the card shows an "Issue self-invoice" button: "Domestic reverse charge (TD16) isn't transmitted to SDI: issuing it assigns the number and posts the VAT integration to the ledger." Until you click it, the document stays a draft with no number and no accounting entry.

6. Find the accounting entry — and understand when it's really created

This is the part that confuses people most: generating the draft doesn't create any ledger entry yet. The VAT integration is only created at issuance — sending to SDI for TD17/TD18/TD19/TD20/TD21, the "Issue self-invoice" button for TD16 — never before. While the document sits as a draft, your accounting and VAT registers know nothing about it.

Once the integration is created, it's a neutral double-entry posting: input VAT (deductible) as a Debit = output VAT (owed) as a Credit, same amount, description code AUTOFATT. The date that decides which VAT settlement it lands in — the entry's VAT date — isn't the date you generate or issue the self-invoice: it's the date of the original document, i.e. the purchase invoice the self-invoice comes from. That's because a reverse-charge integration is a single transaction recorded twice, once in the sales register and once in the purchases register, and both records have to fall in the same period — the period of the transaction, not the period in which you got around to issuing the document. Even a self-invoice issued late doesn't move that period: it stays in the period of the original transaction.

If SDI rejects the submission

If you generated and sent a TD17, TD18 or TD19 and SDI rejects it, SamBooks treats the self-invoice as never issued: if the integration entry had already been created in the meantime, it's reversed automatically, with nothing for you to do. Fix the document and generate a new one.

Correcting it: regenerate, don't edit

A self-invoice that's already been generated can't be edited: document type, rate and date aren't editable after creation. If you got something wrong, use Regenerate from the self-invoice's detail page: SamBooks deletes the previous draft — reversing any linked VAT clearing entry — and generates a new one with the corrected data; a notice reminds you of this before you confirm. You can't have two self-invoices for the same purchase invoice: as long as the previous one exists, SamBooks refuses to generate a second.

If something's not working

• I can't find the "Self-invoice" card. Either the invoice doesn't require reverse charge (ordinary VAT transaction, or declared out of scope), or it isn't confirmed yet: the card only appears on a confirmed, posted or paid invoice.
• "Generate and send to SDI" is disabled. The chosen document type is TD16: it's only transmitted internally, with "Issue self-invoice" on the card, after generating the draft.
• I can't generate a second one. One is already linked to this purchase invoice: open the existing one, or use Regenerate to replace it.
• I can't revert the source purchase invoice to draft. If a self-invoice was already generated from it, the "Revert to draft" button stays disabled and the tooltip says why: "Void or delete the linked self-invoice first."
• SDI rejected the submission. Nothing to fix in the accounts: any entry is reversed automatically. Fix the document and generate a new one.

Ask Sam

You can also generate a self-invoice by asking Sam: "generate the self-invoice for purchase invoice 128" produces the same result as the "Generate self-invoice" button on the detail page — a draft, with sending to SDI still a separate step you confirm.

Frequently asked questions

I received an invoice from a German supplier — what do I do? Record the purchase invoice as usual: since the supplier is foreign, SamBooks detects on its own that a self-invoice is needed and proposes TD17 (services). If you bought goods instead, switch the document type to TD18 in the preview dialog before generating.

What do TD16, TD17, TD18 and TD19 mean? They're the four self-invoice/integration types for reverse charge: TD16 for an Italian supplier (domestic reverse charge), TD17 for services from a foreign supplier, TD18 for intra-EU goods, TD19 for goods already in Italy bought from a non-established foreign party.

Does the self-invoice actually get sent to the Italian Tax Agency? For TD17, TD18, TD19, TD20 and TD21, yes: "Generate and send to SDI" transmits the document through the same channel as ordinary invoices. TD16 doesn't: it's a purely internal integration and never goes through SDI.

Why don't I see the accounting entry as soon as I generate the draft? Because it hasn't been created yet: the VAT integration is only posted once the document is actually issued — sending to SDI for TD17/TD18/TD19, the "Issue self-invoice" button for TD16. A draft doesn't touch your accounting or registers yet.

Can I change the document type or rate after generating the self-invoice? Not by editing it: use "Regenerate" from the generated document's detail page, which deletes the previous draft and creates a new one with the corrected data.

Which VAT settlement does the integrated tax land in? The one for the period the original document's date belongs to — the purchase invoice the self-invoice comes from — not the date you generate or send the self-invoice.

Related guides

• Recording a supplier invoice — where every self-invoice starts from.
• Electronic invoice document types — the full TipoDocumento catalog, self-invoices included.
• Calculating the VAT settlement — where the integrated tax lands.
• Recording a journal entry — the neutral entry issuance creates.
• The Sam assistant.