A monitoring system intelligently captures Document Object Model (DOM) events. The DOM events may provide state information that may not usually be captured during a web session. To reduce processing bandwidth, content identifiers may be used to represent some DOM events. Checkpoints may be identified during the web session and a current state of the webpage may be captured to provide replay synchronization. Different data may be captured based on a sequence and timing of the DOM events during the original web session. Data exchanged with third party websites also may be selectively captured to provide a more through simulation of the original web session.