PayCheck

PayCheck is a sandbox tool that demonstrates card-number format validation — for development, testing and learning only. It does not contact banks or verify live cards.

No. It only demonstrates format-level validation in a sandbox. It cannot tell whether a card is active or has funds, and it never contacts a payment network.

Checking that a number is well-formed — correct length and a valid Luhn checksum. It catches typos, not fraud, and says nothing about a real account.

No. PayCheck is a demonstration and does not store card numbers or anything you enter.

Developers and QA testers learning how card validation works, using synthetic test numbers rather than real cards.

Use the Card Generator to create synthetic numbers, or the Card Validator to check a number's format.