My app which uses a Crystal backend is now live on the Mac App Store.
Anyone can install the crystal backend on Linux with
snap install --beta crystal-gchat-server
Then you can make systemd service files to keep the server running.
Link to client app: https://apps.apple.com/us/app/globalchat-draw/id1525630738?mt=12
If you don’t have a mac, we’re in the process of making a crossplatform mobile client in Dart.