Before an invoice is matched or approved, a handful of very cheap checks can be run on it, and they catch a surprising share of both errors and fraud. None of them requires the purchase order or the goods receipt, so they can run the moment the invoice is captured. They are the least glamorous part of payables automation and among the highest-returning.
Identity and duplication
Is this supplier one we have. Has this invoice number been seen before for this supplier. Is the invoice addressed to the right legal entity. These three catch the accidental duplicate, the invoice meant for another company and, importantly, the invoice from a supplier you have never used, which is the shape of the commonest payables fraud.
Arithmetic and plausibility
Do the lines sum to the net, does net plus tax equal the total, is the tax rate one you would expect, is the date within a plausible range rather than in the future or from three years ago. These catch extraction errors before they reach the ledger and cost nothing to run, which makes them the best return in the whole pipeline.
Bank details, checked against what you hold
If the payment details on the invoice differ from the verified details you hold for that supplier, that is a stop rather than a note. Changes should be verified through contact details you already have, by somebody other than whoever received the request, and recorded. This is the check that prevents the largest single loss in payables.
Questions people ask about invoice validation
Should validation block or warn?
Duplicates and bank detail changes should block. Arithmetic and plausibility issues can warn, since they are usually extraction errors rather than problems with the invoice.
Does validation replace the match?
No. Validation checks the invoice against itself and against what you know; the match checks it against what was ordered and received.
How do we catch reissued invoices?
Duplicate detection on number alone will miss a reissue with a new number. Checking amount and date against the same supplier catches more of them.