A Trusted Web Activity runs a Chrome browser full screen in an Android app, meaning there is no browser UI visible in the app, including the URL bar. This is a powerful capability so we need to verify that the app and the site belong to the same developer - hence ‘Trusted’. To verify that the app and the site opened in the TWA belong to the same developer, a TWA uses Digital Asset Links to certify ownership.
Because a TWA is a special case of a Chrome Custom Tab (CCT), it has access to all Chrome features and functionality including many not available to a WebView. If you’re not familiar with Chrome Custom Tabs, this article provides a complete overview. Some of the features of a TWA not available in a WebView include web push notifications, background sync, Chrome form autofill, Media Source Extensions (MSE) and the Sharing API.
Just like a CCT, a website loaded in a TWA shares stored data with the Chrome browser, including cookies. This implies shared session state, which for most sites means that if a user has previously signed into your website in Chrome they will also be signed into the TWA.
