Alert

An alert is an automatic notification that tells a team, without anyone opening a dashboard, when a metric crosses a threshold or departs from its normal behavior.

An alert's philosophy is 'let the data come to you' rather than 'you go to the data'; in a world where no one has time to check ten dashboards daily, an alert surfaces just the few changes that truly matter. But a good alert is hard to build and its biggest enemy is 'alert fatigue': if the threshold is too sensitive, a flood of trivial notifications follows and the team learns to ignore them all — exactly when a real alert also gets lost. There are two kinds: a fixed threshold (if the error rate crosses some percent), simple but blind to season, and anomaly-based, which learns normal behavior and flags departures from it. An alert with no clear action behind it is also useless; every alert must answer 'what do I do now'.