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27 August 2026 · Contabilidade · 4 min read

The pile of supplier invoices is one of the most universal processes there is: they arrive by email, as PDFs, each supplier with its own layout, and someone copies values into the accounting software. It is also one of the processes where AI proves value fastest — as long as the design respects one rule: the accountant approves, always.

Why this was hard before AI

Classic OCR read characters, not invoices. A new supplier template broke everything; an inline discount or mixed VAT required hand-made rules nobody wanted to maintain.

Current models read an invoice like a human: they find the total wherever it is, understand that "shipping" is a cost and tell an invoice from a credit note. The template stopped being the problem.

The loop with AI

The invoice hits the inbox → AI extracts supplier, lines, VAT and totals → classifies against the chart of accounts and that supplier’s history → prepares the entry → the accountant reviews and approves. A repeat invoice with the usual values takes seconds to approve; an anomaly stands out because it arrives highlighted.

The system learns from corrections: reclassify one item and the next similar invoice arrives proposed with the right account.

What can go wrong (and how to design for it)

Models make mistakes. That is why an entry never books itself: it arrives prepared. Totals are validated arithmetically — if the lines don’t add up to the total, the case is flagged. New supplier, out-of-pattern value or a tax ID that doesn’t match: mandatory review.

The right question is not "is the AI always right?" — it is "is the error detectable before it has consequences?". In a well-designed loop, it is.

The essentials

The essentials
AI reads invoices like a human — templates stopped being the problem01
Entries arrive prepared, never book themselves; the accountant always approves02
Arithmetic validation + exception rules make errors detectable03
The system learns from the accountant’s corrections04

Written by Pedro · Founder

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