The Messages icon will display a red notification on the browser tab when there are unread messages. It also shows a tally of unread messages and there's a dark theme or high-contrast mode to choose from.
Besides texting, Messages for web lets users send stickers, emoji, and attached images.
Messages for web is part of a wider feature update for the Messages mobile app, which now also lets users search and share GIFs.
Two more features in the new Messages app are previews of links sent from friends, and the ability to copy one-time security codes from the app with a tap.
As part of its work on RCS, Google announced earlier this year that dozens of carriers and devices makers are including the Android Messages app as the default messaging app. A notable exception is Samsung.