Point any scanning app at a crumpled thermal receipt and you will learn its character. Faded ink, a stamp over the total, tax tables that echo the same numbers three times. Some apps guess. The guess looks confident, lands in your records, and you find the wrong amount three months later inside a tax spreadsheet.
We made a different rule and built the whole engine around it: never confidently wrong. Every amount Catadoc shows must be corroborated by the document itself: the number repeats on a card slip, or the line items genuinely add up to it, or a machine-readable code on the paper carries it. No corroboration, no answer. An empty field is recoverable. A wrong one poisons everything downstream.
Empty is an invitation
When the paper defeats the reader, the fact is not gone. Tap the empty field and Catadoc shows you the scan's own text with the likely values already highlighted. Tap the right one. Done. No retyping, and the value is provably from your document.
Your correction is final. The engine can re-read the document a hundred times; it never overwrites what you set. The app marks it, quietly: set by you.
Fix it once
Here is where it compounds. Receipts from the same shop look alike. When you fix the total on one receipt from your supermarket, Catadoc remembers where that shop prints its total. The next receipt from the same shop that defeats the reader fills itself, from your one correction.
Why we tell you this
Every document app claims accuracy. We would rather claim honesty: precise when the paper allows it, silent when it does not, corrected by you in seconds, and better for your shops every week you use it. That is what understanding your paperwork should feel like when it is built for you, not for a demo.