XO is a web interface to visualize and administrate your XenServer (or XAPI enabled) hosts.
It aims to be easy to use on any device supporting modern web technologies (HTML 5, CSS 3, JavaScript) such as your desktop computer or your smartphone.
XO is developed by Vates, a French company specializing in Open Source, and released under the AGPL v3 license.
XO is evolving fast, so check the known bugs file first.
Would you like to know more? Check this:
Xen Orchestra has three bugtrackers: one for the server, one for the interface and the last one for common issues or when you don't know to which part it is related to.