VIX allows you to automate virtual machine operations and is the engine behind for example VMware's vmrun command.
Supported on VMware Workstation 6.0.x and up, VMware Server 1.x and up, VMware ESX3.5U2+
The link for the API page no longer offers a working download (strange)
These however works, but you do need to login:
However you might have problems installing.
A few notes, before VMware Workstation 16.x, on Windows you would need to install VIX manually for VMware Player. For VMware Workstation Professional however it comes bundled with VMware VIX and installs it on your behalf.
So for older versions of VMware Workstation, you can install Workstation and use VMware Player from that install. Player will even continue to work after the Professional trial runs out.
For VMware Workstation 16.x, on Windows hosts VIX is already installed for both VMware Workstation Professional as well as VMware Player. It is also installed on Workstation for Linux afaik.
That leaves us with VMware Player 16.x on Linux hosts. It does not come with VIX pre-installed at this time.
Trying to install VIX 1.17 from above generates errors. Apparently you can work around that 1 by renaming /usr/lib/vmware-installer into /usr/lib/vmware-installer_OFF (thanks Minir)