Hungary Invoices (NAV Online Szamla 3.0 reporting API) MCP server

Report a Hungary invoice to NAV Online Számla 3.0 (számla adatszolgáltatás) — the national invoice-data reporting API of the Hungarian tax authority (NAV). This is REPORTING, not issuing: the merchant issues the actual invoice to the buyer; this tool submits the invoice data to NAV as legally required and returns a transactionId. Bring your own technical-user credentials via headers, all self-minted in the Online Számla web portal (onlineszamla.nav.gov.hu -> Technical users): x-nav-login, x-nav-password, x-nav-signkey, x-nav-exchangekey, x-nav-taxnumber (your 8-digit tax number). Runs against the NAV TEST environment by default (no legal effect); set header x-nav-mode: prod to report real invoices. The server exchanges a token, builds the InvoiceData XML, signs the request (SHA3-512), submits a CREATE operation, and returns the transactionId — then call query_transaction to read the processing result. Amounts are in HUF; each line carries a NET unit price and a Hungarian ÁFA (VAT) rate (27, 18, 5, or 0) — the server computes per-rate net/VAT and the invoice gross total.

Check the NAV processing status of an invoice-data submission by its transactionId (returned by submit_invoice). Status values (per invoice index): RECEIVED (NAV received it), PROCESSING (validating), SAVED (stored — non-fatal warnings possible), DONE (successfully processed and stored — this is the success terminal), ABORTED (rejected — read validation_messages for the reason). Authenticates with your technical-user keys; safe to call anytime.