Application performance monitoring services have been around in the IT world for a good amount of time now. Recently the tools have evolved into more meaningful and efficient way to monitor Application environment.
APM strives to detect and diagnose complex Application performance problems to maintain an expected level of service.
Some of the APM tools further can be configured to take corrective action against a failure of service.
Some of the industry leading APM tools are AppDynamics, New Relic, Nagios, SolarWinds, Splunk, and Dynatrace etc.