A machine code API can be loaded onto an eight-bit, register-based virtual machine. A higher level script that is interpreted by a script interpreter of the virtual machine can then use the new functionality provided by the added API. The API may, for example, provide access to hardware of the underlying platform that is otherwise inaccessible to a higher level script. The API loading feature sees use where the virtual machine is remotely deployed in the field but can be communicated with via a bidirectional link. The API is communicated to the virtual machine via the bidirectional link and the API is loaded onto the virtual machine. The API is assigned a reference that a higher level script can use to call the API. Using this feature, various APIs can be loaded and their operations tested. Unwanted machine code APIs can also be erased from the virtual machine.