A method for monitoring an application, comprising: receiving a message from the application; storing the message in a message data buffer in a data store; selecting one or more module instances to define a monitoring function for the application, each module instance for independently performing a respective aspect of the monitoring function, each module instance independently accessing the message data buffer directly from the data store to process data contained therein to perform its aspect of the monitoring function; and, initiating operation of the one or more module instances in accordance with a schedule defined by one or more routing rules, the one or more routing rules for routing a pointer to the message, as stored in the message data buffer, between the one or more module instances to thereby perform the monitoring function without passing the message itself between the one or more module instances.