Most small businesses already look for duplicate payments the same way: export the AP history, sort by vendor, and scan for two rows that look alike. That catches the easiest case — the same vendor, same amount, same invoice number, a few rows apart. It is much weaker at the cases that actually cost money: a re-entered invoice number with one digit changed, a resubmission that lands weeks later instead of days, or telling a real duplicate apart from a rent payment that is supposed to repeat.
| Question | Where to answer it |
|---|---|
| The same vendor and invoice number, paid twice, right next to each other after a sort? | Either — a spreadsheet sort finds this fine. |
| Same vendor and amount, but the invoice number was re-typed with one digit off? | This tool — it measures the edit distance between invoice numbers and flags a likely re-entry a sort would scatter across the sheet. |
| The same bill paid twice, three weeks apart, under a different reference? | This tool — groups by vendor and amount across the whole export, not by adjacency after a sort, and reports the gap in days. |
| Is this flagged pair an actual duplicate, or just my recurring rent? | This tool's confidence tiers — an invoice-number match is high confidence, a same-amount/near-date match with no invoice link is labeled “review” and says so explicitly. |
| Building and maintaining the sort, filters, and formulas myself? | A spreadsheet — and re-doing it by hand every time you want to check a new export. |
| Is my payment data uploaded anywhere either way? | No, on either — but this tool needs no formulas, no pivot table, and no manual re-sort to check the next export. |
No account and nothing installed: it is a static page, the parsing and matching run in your browser, and your vendor names, amounts, dates, and the file itself stay on this device — nothing is uploaded anywhere.
Sorting by vendor finds the easy case: the same vendor, the same amount, the same invoice number, sitting a few rows apart. It does not find a duplicate that only looks different because of how it was re-entered — a typo'd invoice number, a payment recorded three weeks later under a new reference, or a partial-amount resubmission — because those rows sort next to entirely unrelated payments instead of next to each other. This tool runs three separate matching passes (exact invoice match, near-identical invoice numbers, and same-amount payments within a date window) across the whole export at once, so a duplicate that a vendor-sort would scatter across hundreds of rows still gets grouped and flagged.
INV-40219 and INV-40129 look identical at a glance in a column of a few hundred rows, and a plain vendor sort places them wherever their own invoice number falls — not next to each other. Catching that by eye means noticing a one-character difference in a string you were not specifically looking for. This tool measures the edit distance between invoice numbers within the same vendor and amount, and flags anything within two characters of another payment as a likely re-entry of the same bill, whether or not the two rows happen to be near each other.
It does not avoid it entirely -- a genuine duplicate and a recurring charge can look identical from amount and vendor alone -- but it does not treat them the same way. An exact invoice-number match or a near-identical invoice number is high confidence, because a real recurring bill is issued under a new invoice number each cycle. A same-amount payment with no invoice link at all, landing within your chosen date window, is labeled "review" and says explicitly to check whether that vendor is paid this amount on a regular schedule before treating it as anything else. A spreadsheet sort returns the same rows either way, with no confidence tier to tell you which is which.
No. An ongoing ledger that tracks every vendor and every payment over months or years is still the right place to keep that record. This is a one-time check you run against an export from it — did any of these payments go out twice — and it keeps no copy of your data once you close the tab.
Weighing a full AP automation platform instead? See this tool vs. BILL (Bill.com). Considering a contingency recovery-audit firm? See this tool vs. PRGX.