There is one more amp-iframe application that's worth exploring here. Earlier in the book, we built an e-commerce prototype, with configurable product options, a product image carousel, and a shopping cart. But what e-commerce prototype would be complete without a checkout process? Let's see how AMP can accommodate us here.
Completing the e-commerce prototype is difficult in AMP due to JavaScript restrictions. However, it's possible to build a checkout solution combining amp-iframe with a recent HTML5 API: the Payment Request API. First, what is the Payment Request API?
