AussieInvoice freezes an invoice at issue and preserves the PDF generated at that moment as the original document. Corrections are made with credit notes or a replacement invoice, never by editing the issued record. Most invoicing tools let you edit an issued invoice in place and keep only an audit trail of the change.
An issued invoice is a document you have already sent to someone else. They have a copy. Their bookkeeper may have entered it. If your copy can still change, the two can silently diverge, and the version in your system is no longer evidence of what you actually sent.
That divergence is exactly what surfaces in a dispute or a review — the moment when the record matters most and when 'we edited it later' is the worst available answer.
Immutability also removes a category of accident: correcting a typo on an invoice a client has already paid, and quietly breaking the match between the payment and the document.
The same way the correction is meant to be recorded: with a document that reverses or adjusts the original rather than overwriting it.
A credit note reduces or cancels the amount on an issued invoice, referencing it explicitly. Where the invoice needs to be replaced outright, you cancel it with a credit note and issue a new one.
The result is a chain of documents that explains itself: this was issued, this adjusted it, this replaced it. Anyone reading it later — your accountant, your client, you in eighteen months — can reconstruct what happened without needing an audit log.
At the moment of issue, AussieInvoice generates the invoice PDF inside the same transaction that marks the invoice issued. That file is stored and kept as the original.
It is not regenerated on demand from current data. This distinction matters more than it sounds: a PDF re-rendered from live data reflects today's business details and today's template, not what your customer received. If you changed your address or your logo since, the 'original' would quietly change too.
The preserved file is the document that was sent, permanently.
Anyone whose invoices are commercial documents rather than payment prompts: contractors invoicing businesses, consultants working to statements of work, anyone whose client has a procurement process, and anyone who has ever had an invoice queried months after the fact.
It matters less if you invoice consumers for small amounts and the invoice is essentially a receipt. Editability is more convenient and the risk is low.
Note that immutability is a constraint, not only a feature. If you routinely tweak invoices after sending them, you will find it obstructive — which is rather the point, but worth knowing before you switch.
AussieInvoice is Australia-first invoicing for sole traders and small B2B service businesses. Pricing is a pre-launch preview and plans cannot be purchased today.