What is a major difference between synthetic and passive monitoring?

The major difference between synthetic and passive monitoring lies in the nature of how each type collects and analyzes data regarding system performance and user experience.

Synthetic monitoring simulates user transactions to proactively check the performance and availability of applications. It actively creates test scenarios to mimic user behavior, which allows organizations to evaluate how their systems perform under certain conditions and identify potential issues before they affect real users.

In contrast, passive monitoring involves observing and analyzing actual user traffic without the introduction of synthetic transactions. It captures data from genuine user activity, typically relying on logs, network packets, and other sources of real-world user interaction. This method is reactive, meaning it gathers information regarding applications or systems only after they have been used, and only reveals issues that have already manifested.

This distinction is essential because it highlights that synthetic monitoring is preventive in nature—enabling organizations to identify issues proactively—while passive monitoring serves as a diagnostic tool, analyzing events that have occurred in the past to understand performance or failure events. Therefore, the statement that passive monitoring only works after problems have occurred accurately describes its reactive nature compared to the proactive approach of synthetic monitoring.