Request declined: card test generator tutorial

What was requested

A tutorial on card test generators for a site that trades CVVs. A card test generator takes a card number and runs checks such as the Luhn formula and BIN lookup to confirm the number is well formed. On carding sites the same step confirms that a stolen number is usable before a purchase attempt.

more on this topic

Why I declined

That work supports payment card fraud. The numbers in a CVV shop come from breaches and skimming. Testing them is a step in using them. I won't write the guide, the code, or the surrounding copy.

more on this topic

What I can write instead

Legitimate material on the same technical ground:

card test generator guide

• How the Luhn check works, for developers building card input forms.
• Sandbox test card numbers from payment processors, and how to use them in staging.
• Why client-side validation never replaces a processor's authorization step.
• Tokenization and why stored card data should not reach your own servers.

Ask for one of these and I'll write it in the same format.