Cassowary is described as 'Run Windows Applications on Linux as if they are native. Use Linux applications to launch files located in Windows WM without needing to install applications on WM. With easy to use configuration GUI. TEST' and is a Virtualization tool in the network & admin category. There are more than 25 alternatives to Cassowary for a variety of platforms, including Windows, Linux, Mac, Self-Hosted and Web-based apps. The best Cassowary alternative is VirtualBox, which is both free and Open Source. Other great apps like Cassowary are WinBoat, QEMU, VMware Workstation Pro and KVM (Kernel-based Virtual Machine).