Backend & systems·Observability and operations
you record a number over time so you can see the shape of the whole system at once without reading a single log line.
Metric
Also calledtime series, counter, gauge
An aggregated numeric time series: counters, gauges, histograms. Metrics are cheap, bounded in volume and ideal for alerting and dashboards. They cannot tell you about one specific request, which is where logs and traces take over.