Links to other sites with information on the VXSDR:

GitHub: VXSDR Host Library

Source code for the VXSDR host library, released under the GPL v3.

ReadTheDocs: VXSDR Host Documentation and API Preview

Documentation for the VXSDR host API, including build and installation instructions and the complete API reference.

Crowd Supply: VXSDR-20-160 Pre-Launch Page

The Crowd Supply page for the VXSDR-20-160; sign up there for launch notification.