: Stripe uses advanced algorithms and databases to verify the credit card details. This includes checking the credit card number (PAN), expiration date, and security code (CVV) against a database of valid numbers.

: This suggests your Stripe checkout is being targeted by "carding" bots. You should immediately check your Stripe Dashboard for a high volume of failed or $1 transactions and consider enabling Stripe Radar to block these automated attacks.

Stripe provides a fully-featured with dedicated test card numbers. For example: