SAF-T (D406) for small companies: where to start

What SAF-T is

SAF-T (Standard Audit File for Tax), filed in Romania through the D406 declaration, is the standard audit file required by ANAF. It is a detailed XML file that gives the tax authority a structured, complete picture of the company's accounting in a uniform format.

Unlike a summary return, D406 goes down to the level of individual documents and ledger entries, which means the data must be clean throughout the month, not just at the totals level.

The stated goal is to shorten audits: instead of requesting ledgers and documents one by one, the inspector receives a single file, in a format that can be queried automatically. For the company, this means the data must be not only correct but also complete and structured exactly as the schema requires.

What the file contains

D406 is organized in sections that cover the whole of the accounting:

• Master files: the chart of accounts, customers, suppliers, products, and other reference data.
• Source documents: issued and received invoices, payments and receipts.
• Accounting entries: the journal entries from the general ledger.

Data consistency

The sections are not independent. Account balances must match the source documents and the journal, otherwise the file flags inconsistencies. That is why accounting kept correctly day by day produces a correct D406 almost automatically.

In practice, most errors are not arithmetic but mapping errors: an account with no counterpart, a partner without a valid tax code, or a document missing mandatory fields. These do not show in a summary return, but they surface immediately at D406 validation.

How often it is filed

The frequency depends on the taxpayer category: reporting is monthly or quarterly, depending on the VAT tax period and the company's classification. Smaller companies enter the obligation in phases.

For the first filings there is a grace period, during which delays and some errors are not penalized immediately. This is the ideal moment to run the file as a dry run and correct the data, not to postpone it.

It is worth confirming the company's classification and the applicable period early, because the date from which D406 becomes mandatory differs from one category to another.

Validation and first steps

The D406 file is validated with the official DUK validator (DUKIntegrator), which checks the XML structure and part of the content rules. A file that fails validation is not worth sending.

Clarito generates and validates D406 automatically from data already recorded, so reporting becomes a verification step rather than rebuilding the accounting at the deadline.