Google is bringing its digital wallet to the iPhone with the release of the Google Wallet app - a challenge to the Passbook program that Apple has built into the iPhone's operating system. Both apps allow iPhone users to store loyalty cards from some merchants and scan coupons offering discounts.

Google Wallet also allows its users to send money and make purchases on some mobile websites by storing a debit or credit card account on the app. Payment information can also be stored in Passbook.