FAQ & troubleshooting

Does a valid result mean the NIF/IBAN actually exists?

No. pt-fiscal checks structure and check digits only. A NIF can be structurally valid but never assigned; an IBAN can be valid but closed. Confirming existence requires the AT or the bank.

validateNif returns false for a number I believe is valid

Check three things: it has exactly 9 digits, the leading digit/range is a recognized taxpayer type, and the mod-11 check digit is correct. entityType() returns 'desconhecido' for an unrecognized leading digit — that also makes validateNif return false.

Can I use it in the browser / edge runtimes?

Yes. It's pure ESM with no runtime dependencies and no Node-specific APIs, so it runs in browsers, workers and edge functions as well as Node.

How do I actually render the invoice QR code?

buildInvoiceQRCode() returns the AT field string; render it to an image with any QR library (e.g. qrcode). See Invoicing. pt-fiscal deliberately doesn't bundle a QR renderer to stay dependency-free.

The Q (hash) field — where does it come from?

From your certified invoicing software's digital signature. pt-fiscal composes the payload but does not generate the signature/hash; official invoices must be issued via the Portal das Finanças or AT-certified software.

Is the tax logic official?

No — figures and helpers are a convenience for management, not official tax advice.