This plugin details basic usage of the FoxAPI to get a player's balance in a custom command using the FoxAPI.
To build from source, you will need to obtain a HytaleServer.jar file, which requires you to own Hytale. View Hytale's documentation on downloading a jar here
Next, you need the FoxAPI jar, which can be downloaded from BuiltByBit or built from the Github Repo
Once you have a HytaleServer.jar and FoxAPI.jar files, create a directory called libs/ in the project root directory, and place the HytaleServer.jar and FoxAPI.jar files in the folder.
You can then build it using Maven from your IDE of choice.
In IntelliJ Idea, click the Maven logo on the right hand side, click FoxEconomy, Lifecycle, and then double click install.
This will create the FoxEconomy jar in the target/ folder.