<ul data-eligibleForWebStory="true">Prometheus is an open-source monitoring and alert toolkit for collecting and storing metrics.It uses time-series database storing data points with timestamp and 'labels'.PromQL allows querying metrics. Types of metrics include Counter, Gauge, and Histogram.The article provides detailed steps on using Prometheus in Go for monitoring applications.It covers metric types, Prometheus Query Language, and setting up Prometheus with Docker.