Every invoice issued in Hungary is reported to NAV, the tax authority, by the seller's invoicing software through the Online Számla system. The report reaches NAV within seconds and carries the invoice's data line by line. As a buyer, your company can query that data for every invoice that shows its Hungarian tax number.
Querying on the Online Számla website
Sign in at onlineszamla.nav.gov.hu with your Ügyfélkapu+ or DÁP credentials. The company's primary user, or a user the primary user has given query rights, opens the invoice query and selects the buyer side to list invoices received. Results can be filtered by date and supplier, opened to see the reported lines and exported.
Querying through the API
Accounting software uses a technical user, which only the primary user can create. Its query operations take a direction: OUTBOUND for invoices you issued, INBOUND for invoices issued to you. A digest query lists the invoices, and a data query returns the full reported data of one. The interface specification is published in Hungarian and English.
What the query cannot find
The buyer side only finds invoices whose buyer field holds your Hungarian tax number. An invoice without it, or a receipt from a till, does not appear. And the result is the data the seller reported, not the invoice document itself: keep the invoice you received as the record.
Receipts and the eNyugta app
Retail receipts come from online cash registers, and a new generation of electronic registers has been in use since summer 2025. NAV's eNyugta app, in Hungarian and English, lets a customer keep those receipts digitally and review their spending.
Keeping the rest
The receipts Online Számla never sees, from tills, trips and foreign suppliers, still need a copy. Smartbills keeps them from a photo in the app or from the email they arrived in, with items, every tax and the total.