Case study

One zero was missing from the variable symbol

A client paid our invoice in two payments and mistyped the variable symbol in both. The money was in the account, but the invoice stayed marked unpaid in the system, until we taught Kovrin to recognise that kind of typo.

Norbert Kovalčínfounder · STENVARD24 September 202624 September 2026

What happened

The invoice had the variable symbol 2026010003. The client paid it in two payments and wrote 202601003 in both. One zero was missing.

The bank credited the money. But matching by variable symbol did not link it to the invoice, because the symbol did not match. The invoice stayed in the system as unpaid, in full.

It happens. People make mistakes, even careful ones.

You know that moment. Someone opens the statement, looks for the amount, compares names and matches it by hand. Or a reminder can go out for an invoice the client has already paid.

What we changed

Stenvard keeps its own invoices in Kovrin, so we dealt with this on ourselves straight away.

When the exact variable symbol does not match any open invoice, Kovrin checks whether it could be a single human error: a missing, added or mistyped digit. A suggestion is only created when three conditions hold at once:

1. the symbol differs from the invoice by exactly one such error,
2. the payment currency matches the invoice currency,
3. the amount fits within what is still owed on the invoice.

And there must be exactly one such invoice.

A suggestion you would have to check as thoroughly as searching from scratch would not save you work, it would only hide it.

When the variable symbol matches exactly, the payment is matched as before. A suggestion only comes into play once an exact match is missing.

The third condition matters. Invoice numbers run in sequence and often differ only in the last digit. Without checking the amount, a suggestion could easily hit the neighbouring invoice.

Who decides

Kovrin does not match the payment to the invoice by itself. Next to the transaction, it shows “Kovrin suggests” and pre-fills the invoice. You confirm the match, with one click. Until you do, the invoice does not change.

What it gave back

Both payments, which the system had not been able to see until then, appeared against the correct invoice as a suggestion. Searching through the statement was reduced to one click.

We also tested it the other way round, on real data. Kovrin suggested a payment that exactly settled an invoice. It did not suggest a higher payment that would have overpaid the invoice, even though it had the same typo in the symbol.

We also deliberately switched off the safeguards, once the amount check, once the one-invoice limit. The tests caught it every time.

In an operations audit, we look at how many of your payments stay unmatched today, and why.