Creditcard verification with regex?

Question

What is the right way to verify a credit card with a regex? If which one to use there are tons online. If not how to verify?

Answer 1

That depends on how accurate you want your pre-validation to be. To validate everything you can, you need to compute what the last digit of the card should be and compare to what is entered, which a RegEx cannot do.

For the algorithm and other details see this link, which also provides a list of common number prefixes that you could validate against.