CFOP Validator

You are putting together a Brazilian invoice and the accountant sent a four digit code over chat: 5.102. Before typing it into the issuing software, you want to be sure it makes sense. Is it an inbound or an outbound operation? Does it cover a sale inside the state or across state lines? Getting the first digit wrong is the kind of mistake SEFAZ rejects on the spot, or worse, lets through and turns into an ICMS headache months later.

The check strips dots and dashes, then looks at the leading digit, which carries the nature of the operation: 1, 2 and 3 are inbound (same state, another state, abroad) and 5, 6 and 7 are the matching outbound codes. Notice that no CFOP starts with 4, 8 or 9, so typing 4102 returns an unrecognized prefix message. The first two digits are displayed apart from the last two purely to make the code easier to read.

The part that matters: this checks the shape of the code, not whether it exists. Something like 5000 passes as valid because it has four digits and an accepted prefix, even though the official table has no such entry. Use it to catch typos and inbound versus outbound mixups, then confirm the exact meaning (5102 is a resale of goods bought from third parties) in the official CFOP table or with your accountant. Everything runs in your browser.