Built-ins and rewriters may be developed to extend the capabilities of OntoBroker. They allow developing access functions to arbitrary systems, to develop any function needed or to introduce additional data into the inferencing process. The basic architecture of the inference engine is a system graph. In this graph, tuples flow from one vertex to the other vertices. A built-in is such a vertex. This means that it receives tuples, completes them and sends away the completed tuples.
The CustomerIDE provides an eclipse-based environment for developing own OntoBroker extensions. It already contains code examples and unit tests for builtins, commands, connectors, rewriters and dynamic webservices.