Xen is described as 'Org, home of the Xen hypervisor, the powerful open source industry standard for virtualization. It is a native (bare-metal) hypervisor providing services that allow multiple computer operating systems to execute on the same computer hardware concurrently' and is a popular Virtualization tool in the network & admin category. There are more than 25 alternatives to Xen for a variety of platforms, including Linux, Self-Hosted, Windows, Mac and NVIDIA vGPU apps. The best Xen alternative is VirtualBox, which is both free and Open Source. Other great apps like Xen are KVM (Kernel-based Virtual Machine), Distrobox, OpenStack and UTM.
Open-Source. Self-Hosted. Good documentation.