The credit card checker app is a very useful tool that can be used to check the validity of a credit card number. This tool uses a Luhn algorithm, which is a popular method for validating numbers. It also has the ability to send an email to the user, informing him of his or her eligibility.

This is a simple and easy-to-use tool, which can be used by anyone who needs to check the validity of a credit card number. It is very easy to use and has a very simple interface.