PCI and test data
Never use real card numbers in dev environments. MockCard generates disposable test credit card numbers with CVV and expiry — designed to pass client-side validation while failing or succeeding at the gateway layer predictably.
Pair numbers with webhooks
A test credit card number is only useful if your backend reacts correctly. MockCard fires payment_intent.succeeded or payment_intent.payment_failed with decline codes so you can assert order state in automated tests.