ThingWorx Flow SDK is a library that is needed to build ThingWorx Flow Custom connectors.The library is required for a package to be recognized as a connector by the ThingWorx Flow server. In addition to this it provides infrastructure functions like loggers, time and date utility functions etc. ptc-flow-sdk is automatically added as a dependency of the custom connector when a new connector is created using the ThingWorx flow CLI.
For detailed information on creating new connectors refer to the ThingWorx Help Center .