Prometheus

Prometheus is a monitoring system with a built-in time-series database and the PromQL query language. It pulls metrics from monitored targets and is used for infrastructure and application monitoring. It is developed by the Prometheus open-source project, which was originally built at SoundCloud and has existed since 2012; that date marks the project's inception rather than a public release. It is licensed under Apache-2.0, an open-source licence, and there is no commercial edition from the project itself. It is run self-managed. The latest release is v3.15.0, dated 25 September 2026. The software is free to use, so cost depends on the infrastructure it runs on. Buyers should understand that Prometheus is primarily a monitoring tool and the time-series database is local storage within it, so it is not a general-purpose time-series database in the way some other products on this list are. Teams that need a database for application data, or that need long retention across many servers, should check how that fits their needs before choosing it. Prometheus suits teams that want to collect and query operational metrics and raise alerts, with a query language built for that task. The project shows as active.