Check if a Card is Valid Without Charging it
How can I make sure my customer entered a valid card number before attempting to charge it?
You can verify the card details, as well as see the results of the CVC and Zip Code checks, by saving the customer’s card in Stripe.
The card information is verified when the card is saved, but it only verifies that the information is valid: it cannot check credit limits or account balances to guarantee that a card will have sufficient funds when you do decide to charge it. The card may still be declined or fail for other reasons.