For Example number 4 for Visa credit cards, 5 for MasterCard, 6 for Discover Card, 34 and 37 for American Express and 35 for JCB Cards. So in this way you can serve your purpose of using a specific site without having to share your financial details with it if you have no aim of processing any payments on it.Ī valid credit card number can be easily generated using credit card generator by assigning different number prefixes for all credit card companies. It is crucial to use a credit card generator when you are not willing to share your real account or financial details with any random website. Credit Card Generator allows you to generate some random credit card numbers that you can use to access any website that necessarily requires your credit card details.