What "once" actually means
In most setups an invoice is written two or three times: in the invoicing app, then in the accounting one, then into a spreadsheet tracking due dates. Every copy is a chance to get it wrong, and the discrepancy usually surfaces at the trial balance, a month later.
Here the issued invoice produces the journal entry directly, goes out to the tax portal, lands in the customer's balance and draws down stock if it carries inventory lines. This is not a sync between modules — it is one document seen from several angles.
The exchange rate is stored on the document
Foreign-currency invoices use the central bank's rate for the day before issue, as the tax code requires, and that rate is persisted on the invoice.
The detail matters: recompute the rate later and the local-currency value of an old invoice changes, so a trial balance from three months ago no longer matches what you filed. Historical rates are never recalculated.
Series, numbering and duplicates
Separate series per work point, with continuous numbering. The system refuses to issue two documents with the same number — not by convention, but because it cannot.
Every document type in one place
Proforma, delivery note, receipt, estimate, credit note, advance invoice. A credit note is a reversing entry, not an edit: a posted invoice stays exactly as issued, because the law requires it and because otherwise the ledger would stop being trustworthy.
Recurring invoicing and collections
Subscriptions issue themselves on schedule, with a payment link in the email. Due dates feed the cash forecast, and overdue balances raise a notice before they become a problem rather than after.
What it costs
Invoicing is free and unlimited, including on the free plan. There is no monthly invoice cap, because e-invoicing is mandatory here and we do not charge for obligations.