Use this playground environment to experiment integrating Google Pay, as if you were working directly from your own checkout page.
Google Pay is loaded from your index.html file, and once completed, the function onGooglePayLoaded in the index.js file is called. This is your stating point to integrate Google Pay in this playground.
If you are interested to find out more, go check out a basic guided tutorial on how to integrate Google Pay API on the web, the library reference and the list of participating processors.