Plugins are modules that extend functionality of tools in either Ready! API or SoapUI (open source). They are developed in Java, and use the Plugin Framework which provide annotations and interfaces that can be used to extend or modify functionality.
They are distributed as a single JAR file containing all the plugin functionality and all needed 3rd party libraries.
Some possible uses for plugins are:
Integrate with other tools, platforms or technologies.
Tailor functionality for specific APIs.
Add new functionality for existing protocols.
Add new protocols or API types.