The API provides notifications that can be used to augment the administrative and monitoring interfaces typically available in proxy caches through Web-based tools, command-line monitoring, and SNMP. The event notification for logging allows the proxy to extract real-time information and manipulate it in a convenient manner in order to feed external consumers of this information. For example, content distribution networks and web hosting facilities may use real-time log monitoring to provide up-to-date information to customers about traffic patterns and popularity on hosted web sites, or to notice high rates of ``page not found'' errors and dynamically create pages to redirect users to the appropriate page. While all of this information can be obtained in off-line post-processing of access logs, the API allows deployers to implement custom modules that meet their specific needs for realtime analysis and action.
The administrative interfaces of the API can also be used to monitor networks of proxies, and to combine this information with other sources in Network Operation Centers (NOCs). For example, if a company is running a network of proxies and notices an unusually low request rate at one such proxy, this information can be combined with other information to help diagnose congested links or overloaded systems beyond the company's control. Since the proxy is functioning normally, one isolated measurement provides less reliable information than programmatic and comparative measurement of different systems.