Since the Kato team messaging service doesn't have proper desktop apps, many people use Kato in the browser. The main issue with this approach is the high possibility of missing incoming messages.
Here's a nifty lifehack (courtesy of Boris Soroker) that makes it easy to never miss a message:
Keep your detached Kato tab all the way to the right of your screen, with all other windows on top. This way, you'll always see the state of your unread ”pills”.