Card.io essentially just types in the information on the front of the card for you (card number, cardholder name, expiration date). For most applications, you p

Card.io essentially just types in the information on the front of the card for you (card number, cardholder name, expiration date). For most applications, you probably still need to type in the billing zip code and CVV (https://en.wikipedia.org/wiki/Card_security_code https://en.wikipedia.org/wiki/Card_security_code) found on the back of the card.