Extract IBANs, Currencies, and Addresses from Financial Documents — Validated, Not Just Strings

Regex Doesn't Understand Financial Data You need to extract an IBAN from a bank statement. So you write a regex. It matches something that looks like an IBAN — starts with two letters, followed by two digits, followed by up to 30 alphanumeric characters. The pattern matches. You store the result. Except the regex can't validate the IBAN. It doesn't check the country-specific length. It doesn't verify the check digits. It matches "DE89 3704 0044 0532 0130 00" and "DE00 0000 0000 0000 0000 00" wit