Application Performance Monitoring (APM) tools are used to ensure that applications are running smoothly and meeting user expectations. They collect key metrics such as response time, throughput, and error rates, and enable developers to identify performance bottlenecks.
One common use case for APM is detecting slow response times in web applications. By instrumenting the code with APM tools, developers can detect performance degradation. Metrics from the APM can guide them towards the part of the architecture causing the performance drop.
However, APM fail at actually identifying where or why the drop in performance occured. Developers are required to pattern-match or rely on previous experience to guess the root cause of the issues. This is why modern application rely on observability tools such as distributed tracing or wide events that have proven to be a better fit to quickly resolve incidents.