Quick replies were first introduced around two years ago with Android 7.0 Nougat, making it more convenient for everyone to respond to messages without having to open a new app for each one. Google is now testing quick replies for Chrome on Android, though the feature isn't yet accessible to any of us commonfolk.
Websites can already send notifications via Chrome on Android devices, but quick reply support would make things much more streamlined for chat-related sites. PWAs in particular would greatly benefit from this addition.
Unlike many of the flags we spy on Chromium Gerrit, this feature isn't available for any public Chrome channel yet. So for now, you'll have to sit tight. We'll let you guys know when we hear more information on the topic.
- Chromium Gerrit
- XDA Developers