Payment Request API - Web APIs | MDN
The Payment Request API provides a consistent user experience for both merchants and users. It is not a new way for paying for things; rather, it's a way for users to select their preferred way of paying for things, and make that information available to a merchant.
Registering a web-based payment app
Learn how to register a web-based payment app to a customers' browser. You'll also learn how to debug them.
Receive Payments via Google Play Billing with the Digital Goods API and the Payment Request API - Chrome Developers
Receive Payments via Google Play Billing in your PWA with the Digital Goods API, the Payment Request API and Trusted Web Activity