Our service doesn't just use Websockets, but also a dynamically loaded library (as noted in the system architecture section of our documentation). The latter allows developers to link to the library directly in C++ and Objective-C applications, or through one of the language bindings provided for Java, C#, and Python.
On a broader level, I should note that our SDK terms and conditions don't allow applications that aim to provide their own hand tracking functionality or which are otherwise substantially similar to the features or functionality of our core software.