In the UK, the Wallet app supports the Connected Cards feature with many different banks. This is enabled through a UK standardized Open Banking API.
No such API exists in the US, so Apple has partnered specifically with Discover to enable this feature for Discover US credit cards. The company did not comment on whether other US banks will add support in the future.
If you are running the iOS 17.1 beta and have a Discover credit card in the Wallet app, tap on it and press the button to opt-in and begin the connect card flow. This will involve securely authenticating with Discover.
Once setup, you can see your card’s balance in the Wallet app. The balance is also displayed in the Apple Pay sheet, at time of making a purchase.
Following Apple’s usual privacy standards, any data fetched through the Connected Cards feature remains on device and is not shared with Apple.