The IBAN was introduced to solve a simple problem: every country formatted account numbers differently, so cross-border payments failed often and were expensive to repair. The standard wraps each national format in a predictable envelope.
Structure. An IBAN starts with the ISO country code (DE, FR, IT), followed by two check digits computed from the rest of the string, then the national account identifier — typically a bank code, branch code, and account number. Lengths vary by country (a German IBAN has 22 characters, an Italian one 27), up to a maximum of 34.
Validation. The check digits let any system catch typos mathematically before a payment is sent — a mistyped IBAN almost always fails the checksum. This is first-line error protection, now reinforced in the euro area by Verification of Payee, which matches the recipient's name against the IBAN before a transfer is confirmed.
IBAN vs. BIC. The IBAN identifies the account; the BIC (SWIFT code) identifies the bank. Within SEPA, the IBAN alone is generally sufficient to route a payment.
Why it matters for brands
If your platform pays out to consumers or creators, the IBAN is the one field you must collect and validate. Checksum validation at input time prevents failed payouts and support tickets, and EU rules prohibit "IBAN discrimination" — you must accept any SEPA-country IBAN, not just domestic ones.