For building you own application you can access Z-Wave on two levels: ZIP Gateway or Z-Ware CE Web. I suggest you read the documents for ZIP Gateway and Z-Ware CE Web on this page: http://zwavepublic.com/downloads
The LibZWave application is build on top of the ZIP Gateway interface. But if you are okay with working with Web-sockets you may consider using the Z-Ware CE Web interface.
You may access the Z-Ware CE Web UI through https://raspberrypi.local. The user name is Sigma and password is sigmadesigns.
I hope this helps,