The BIN plays an important role when making online payments with a payment card. This code identifies the card’s issuer, which receives requests for payment authorization. The purpose of this is to validate the card and check whether the account contains sufficient funds. Both authorization and subsequent release on the basis of the BIN take place very quickly in the background during the ordering process.

For bank transfers and direct debits, other numbers are normally used for identification purposes; they include the SWIFT/BIC code and IBAN.

The BIN comprises the first six digits of the (typically) 16-digit credit card number, which is usually embossed on the front of the card. The first one or two digits stand for the credit card company, the next two or three for the card provider, and the last two for the card type (e.g. gold or standard, and main or secondary card). Debit cards usually have the number on the back, or it can be queried from the issuer.