Apple Pay now supports all four major credit and debit card issuers.
Discover Financial Services, the last holdout, announced Monday that it had reached an agreement with Apple allowing its U.S. cardholders to make purchases by passing their iPhone or Apple Watch by a payment terminal.
Visa, MasterCard and American Express already support Apple Pay, which the technology giant touts is a more secure way to pay than traditional card-swiping. Apple doesn't store any card data; instead a unique code is held on the iPhone or other device and a separate one-time code is shared with the store during checkout.
Security is the No. 1 feature on people's minds when considering using some new form of payments, according to a survey released last week by 451 Research. And more people are starting to buy into the idea of using their smartphones as a payment mechanism. In a notable increase from last year, about 24% of those surveyed said they believe mobile payments are more secure than traditional credit cards.
451 Research also noted that two in three people who had tried Apple Pay came away "very satisfied" with the service.
The only security issues to date have affected banks, which didn't properly create a process to vet sign-ups.