sweetgreen for iOS - Order, pay, rewards. It's so clean, you can eat off it.
Pay Finders - Discover and explore local merchants that accept Apple Pay
Vue Storefront - Open Source PWA for any eCommerce
Pay in apps with Venmo - Make purchases in apps using your Venmo account
Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.
The New Google Pay - Pay, save, manage expenses and more