A process for registering applications is disclosed. The applications typically work in a Session Initiation Protocol (SIP) JSR 289 environment. A request to register a application to monitor a communication session is received. A first instruction that identifies a first event in the communication session is received from the application. An event may be the sending of a specific type of packet, such as a SIP INVITE. The first event in the communication session is detected. In response to detecting the first event in the communication session, the application is registered to monitor the communication session according to the first instruction. A notification is also sent to the application to monitor the communication session according to the first instruction.