Improving Monzo Plus - If you were Monzo

[alawrence (Anthony 🛩️)]

Japan running out of credit card numbers

This is actually a really interesting problem. So, you look at the card number and think “16 digits is shit loads, how can they be running out?” So, the first 2 digits are assigned to the card network (3x Amex, 4x Visa, 5x Mastercard,… ) the next 4 digits they give out to issuers like us. For example we own 535522 (our BIN or IIN) for UK Debit cards. The last digit is a checksum. You can use it to verify if a card number is legal (read about Luhn Algorithm). That means we now have 9 digits …