Reference

JavaScript bridge API

Every native method and API a page inside a generated app can use - 568 of them, across 30 families, each with a runnable example. Extracted from the app runtime itself, so this list is exactly what ships.

Check before you call. The bridge exists only inside a generated app. In a browser - including while you are developing - window.WebToApk is undefined, so guard every call and give the page something sensible to do without it.

if (window.WebToApk && window.WebToApk.isOwned('pro_unlock')) unlockPro();
else showWebCheckout();

Anything asynchronous answers with a promise (the helpers and web APIs) or a DOM event - window.addEventListener('appmint:…', …). Every entry has an example that shows which. Start with writing HTML for your app and the Web APIs bridge, which cover the conventions a method list cannot.