01 — Why it reads the same
The network is local, the document is not
InvoiceNow runs on Peppol — the same delivery network used across Europe and in Australia and New Zealand. The access points differ, the participant identifiers differ, and the national requirements on top differ. The document underneath is the same one.
That is why a folder holding an InvoiceNow invoice, a Peppol UBL from Rotterdam and a Factur-X PDF from Paris comes out as one table here rather than three problems. Nothing was built specially for Singapore; the standard did the work.
02 — What is checked, and what is not
Arithmetic, not opinion
Each invoice is held against the EN 16931 rules — every one of them is listed with its number and one sentence on what the failure means. A rule number is something you can quote back to a supplier.
Where a number carries its own check digit, a typo is caught offline: an IBAN does (ISO 13616, mod 97-10), and so do the VAT identifiers of several European states. A Singapore UEN is not checked — its formats and check character are not something this tool can verify, and a correct number reported as wrong is worse than no check at all. Where a check cannot be computed, nothing is claimed.
Two currencies in one folder
Singapore invoices arrive in SGD, in USD, and often in both within the same month. A total is only a total within one currency, so sums are grouped by currency rather than added across. No exchange rate is guessed. A converted figure produced at export time is a number nobody can reconcile against the bank later — and the rate that matters is the one on the day the money moved, which this file does not know.
Paying them, and checking that they were paid
Two neighbouring tools use the same principle. A payment instruction file can be checked before the bank sees it — IBAN check digits, the control sum recomputed, and anything that looks like the same invoice paid twice. A bank statement can be turned into a table, with the closing balance recomputed from the opening balance.
Trying it
Drop files on the main page — up to 10 invoices per export and 20 a day, free, no account, and the count resets at midnight. Pro lifts both limits for 29 € once, with no renewal. To inspect a single file there is the check page.
Nothing is uploaded
The files are read in the browser. There is no server they could go to, and that is checkable in two minutes: open the developer tools, the Network tab, and drop an invoice in — no request goes out. Or load the page, disconnect the network, and drop it anyway. It still works.