Application Performance Monitoring - tools that track how well your application performs and where bottlenecks occur. Like having a fitness tracker for your software that shows which parts are working hard and which are slowing down.
APM tools like New Relic show you that your checkout page takes 3 seconds to load because of a slow database query, not because of network issues.
These services provide monitoring and observability solutions that include APM capabilities, allowing users to track application performance and identify issues.