Business::CreditCard These subroutines tell you whether a credit card number is self-consistent -- whether the last digit of the number is a valid checksum for the preceding digits. If you additionally want to process the credit card electronically, see Business::OnlinePayment Original author is Jon Orwant , The Perl Journal and MIT Media Lab Current maintainer is Ivan Kohler . Please don't bother Jon with emails about this module. Lee Lawrence , Neale Banks and Max Becker contributed support for additional card types. Lee also contributed a working test.pl.