We're building the world's fastest checkout experience at Clover. The Clover app exposes a payment service API to apps and mobile web sites. This is a very different design than PayPal, which doesn't use a native app to provide payment services for mobile web and app purchases.
This is a quick demo of Clover as compared with PayPal on mobile web checkout. You can try it yourself and clover.com/store. This is a preview in our iOS app. Android checkout and a production-quality iOS version will be coming soon. Android checkout is even faster.
Note that users never need to "log in" to Clover. Your account is locked to a device, and your device is locked to an account. Our security architecture uses SSL mutual authentication with the cert and key stored in app-private storage. A short PIN is used to protect against unauthorized physical access.