Yes! VNC Viewer 6.22.826 installs a URI handler that can be called from other programs, like web browsers, to launch a connection to a VNC Server using VNC Viewer.
What is the format needed to launch VNC Viewer using a URI?
The syntax to use it is below.
com.realvnc.vncviewer.connect://<cloud server ID>
Currently the URI handler does not accept any additional parameters other than the VNC Server address, as above.
How do I find the connection information for my VNC Server?
You can find the connection information for VNC Server in several ways.
Using the VNC Server GUI
You can open the VNC Server GUI using either the Start/Applications menu, or by double clicking the VNC Server icon in the system tray. Once open, expand the Other ways to connect section which will list the cloud server ID (all subscriptions) and/or IP address(es) (Enterprise subscription only).
Using the command line
Starting in VNC Server 6.11.0 you can query VNC Server for the cloud server ID on the command line. To do so, look for the ServerId line after running the appropriate command for your platform below.
Windows (elevated/administrator access required)
"C:\Program Files\RealVNC\VNC Server\vncserver.exe" -service -cloudstatus
sudo /Library/vnc/vncserver -service -cloudstatus
sudo vncserver-x11 -service -cloudstatus