VirtualBox 6 has an extremely modular design with well-defined internal programming interfaces and a client / server design. This makes it easy to control from several interfaces at once: for example, you can start a virtual machine in a typical virtual machine GUI and then control that machine from the command line, or possibly remotely. VirtualBox also comes with a complete software development kit: although it is open source software, you don’t have to hack the source to write a new interface for VirtualBox.

 Virtual machine descriptions in XML
The virtual machine configuration settings are stored completely in XML and are independent of the local machines. Therefore, virtual machine definitions can easily be ported to other computers. 

 Guest Additions for Windows, Linux and Solaris
VirtualBox has special software that can be installed on Windows, Linux and Solaris virtual machines to improve performance and make integration much more fluid. Among the features provided by these guest additions are the integration of the mouse pointer and arbitrary display solutions (for example, by changing the size of the guest window). There are also guest additions for OS / 2 with somewhat reduced functionality.

 Shared folders
Like many other virtualization solutions, to facilitate the exchange of data between hosts and guests, VirtualBox allows you to declare certain host directories as “shared folders”, which can then be accessed from virtual machines.