A flexible logging system is described herein that operates with a web server to provide activity logging in a way that is customizable to include a variety of data fields, can capture both client and server log information to a single location, and can provide data to an analysis engine directly to provide near real-time reporting. The system captures events within the web server as they occur and can provide reporting before the final response occurs. During request processing in the web server, server extension modules raise log events whenever an event occurs. The system matches the received data to a log definition and writes the data to any log that matches. Thus, the flexible logging system provides a rich, flexible, and fast platform for content providers and administrators to get a real-time view of the state of requests to their web servers.