Answer
How do you stop paying the same invoice twice?
Updated July 2026 · by the DynamoDocs team
The short answer
Catch it before it posts. DynamoDocs flags a second invoice carrying the same number from the same supplier, and distinguishes a plain resend from a reissue with different figures, because those are different problems needing different actions. Only the later copy is flagged, and resolving it archives one side so the flag actually clears.
A resend and a reissue are not the same problem
Same number and the same total is a resend: the document arrived twice, and the copy is disposable. Same number and a different total means the supplier reissued it with new figures, or one of the two was misread. That is the dangerous case, because one of those amounts is the one you owe and nothing on the flag tells you which. Most systems collapse both into a single 'possible duplicate' warning.
Only the copy is flagged
The earliest document to arrive is treated as the original and left alone. Flagging both would leave the invoice you actually want to pay sitting in review next to its own copy with no way to tell them apart.
Resolving it has to change something
Clearing the flag means deciding which copy survives: archive the redundant one, or mark the new one as replacing the earlier. Either way one document leaves the active set, which is what makes the flag clear. A warning you can merely dismiss comes back on the next check and teaches people to ignore it.
A different supplier reusing a number is not a duplicate
Suppliers number their own invoices and collisions across vendors are routine, so the check is per supplier.
Related questions
What if the second copy is the correct one?
That is the reissue case. You mark the newer document as replacing the earlier one; the original is archived and both records note what happened.
Does it catch duplicates across different formats?
Yes. The check is on the extracted supplier and document number, so the same invoice arriving once as a PDF and once over EDI is still caught.
Is anything deleted?
No. Resolving a duplicate archives a document and records what replaced it; nothing is destroyed.
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