A rule engine system works with physical systems monitored by Internet-enabled endpoints on one hand and developer custom applications on the other. Endpoints operate in both the domain specific language of the rule engine, and communicate with participating applications in the native protocols thereof. Whether new or legacy, whether hardware, software, or firmware, whether having much, little, or no digital processing or communication capacity, the participating application may be monitored and controlled by an endpoint that communicates over the Internet with the rule engine. Individual developers prepare rule language files, containing data and instructions for the rule engine to implement through the end point. Any apparatus, whether exclusively mechanical, electrical, electronic, highly sophisticated electronic, or some combination may be monitored and controlled. Any participating application, from a mechanical lawn sprinkler to an Internet commerce server may be implemented thus.