NAV Online Számla is Hungary's Online Invoice System, run by the National Tax and Customs Administration (NAV). Invoicing software reports the data of each invoice to NAV as InvoiceData XML through a REST interface, now at version 3.0. The report is tax data, not automatically the invoice itself. Klarbon plans to open Online Számla XML; this is not available yet.
What is in an Online Számla report?
| Part | Holds |
|---|---|
| invoiceData.xsd | the business content: seller, buyer, VAT status, lines, VAT rates and totals |
| invoiceApi.xsd | the operations, such as /manageInvoice to submit and /queryInvoiceData to fetch an invoice |
| invoiceAnnulment.xsd | technical annulment of a wrongly sent report |
| Operation per invoice | CREATE, MODIFY or STORNO |
| Encoding | invoice data sent BASE64 encoded, optionally GZIP compressed |
| Property | Value |
|---|---|
| Authority | NAV, the Hungarian National Tax and Customs Administration |
| Current version | 3.0 |
| Reporting | interface introduced in 2018; broader VAT Act scope from 4 January 2021, subject to the stated exceptions |
| Access | a registered technical user, with a signed request and an exchange token |
NAV's interface specification sets out the schemas, operations, legal basis in Act CXXVII of 2007 on VAT and the option to report by electronic invoice (NAV specification, 12 February 2026). NAV publishes the XSD schemas and example XML in a public repository (NAV repository).
Data report or electronic invoice?
| Data report | Electronic invoice in InvoiceData | |
|---|---|---|
| What it is | tax data about an invoice issued elsewhere | the invoice itself, with full data content |
| Marked by | completenessIndicator false |
completenessIndicator true |
| Buyer | anyone | not a private person, and with other limits |
| Use | required for invoices within the reporting scope | the seller's choice, subject to the specification's limits |
What does Klarbon do with Online Számla XML?
Opening Online Számla XML is planned, not available yet. Klarbon does not report invoices to NAV. It opens UBL and CII invoices; see the invoice viewer.
Related
Frequently asked questions
Is the Online Számla XML an e-invoice?
Normally not. The InvoiceData XML is a data report to NAV. Since version 3.0 a seller may choose to issue the full invoice in that XML as an electronic invoice and mark it as such, with limits, for example the buyer cannot be a private person.
Which invoices must be reported?
Since 4 January 2021, the VAT Act requires data on invoices and equivalent documents issued for supplies under the Act, with a narrow exception for some services taxed under a special scheme in another Member State.
Do I need to register?
Yes. A business that reports must register on the Online Invoice System and create a technical user, whose keys the invoicing software uses to sign and send its reports.
Sources
- NAV, Online Invoice System 3.0 interface specification, 12 February 2026 (official repository PDF) raw.githubusercontent.com
- NAV, Online Invoice System interface specification, version 3.0 (PDF) onlineszamla.nav.gov.hu
- NAV, Online Invoice public repository (schemas and examples) github.com
- NAV, Online Számla (in Hungarian) onlineszamla.nav.gov.hu