What is Prometheus?
Prometheus is an open-source systems monitoring toolkit originally built at SoundCloud in 2012 and now a graduated CNCF project. It works on a pull model: a Prometheus server scrapes metrics over HTTP from instrumented applications, exporters, or service-discovery targets at configured intervals, storing the results in its own time-series database.
Read the full overview
Queries and alerting rules are written in PromQL. Prometheus evaluates alerting rules itself and forwards firing alerts to a separate Alertmanager component, which handles deduplication, grouping, and routing to notification channels. Dashboards are typically built in Grafana rather than Prometheus itself.
Sources checked 27 September 2026: Prometheus overview, PromQL basics.
Key capabilities
- Pull-based scraping: Collect metrics from instrumented targets and exporters on a schedule.
- PromQL: Query and aggregate time-series data for graphs and alerting rules.
- Alertmanager: Route, group, and deduplicate firing alerts to notification channels.
- Service discovery: Automatically find scrape targets in Kubernetes, cloud providers, and other systems.
Local retention is limited by design (commonly days to weeks); plan for Thanos, Cortex, or Mimir if you need long-term or multi-cluster storage. Decide who owns alerting-rule changes and Alertmanager routing before scaling scrape targets.
Prometheus fits teams instrumenting their own services (via client libraries or exporters) who want a self-hosted metrics pipeline they operate directly. It is not a full observability suite on its own - logs, traces, and long-term multi-year retention typically require pairing it with other tools (Grafana for dashboards, Thanos or Cortex/Mimir for long-term storage and multi-cluster federation).
A useful trial instruments one real service, confirms an alert fires and routes correctly through Alertmanager, and checks whether local retention and query performance hold up at the target's actual metric cardinality.
Technical details
- Access
- Self-hosted
- Source model
- Open source
- Founded
- 2012
- Headquarters
- CNCF Project
- Pricing model
- Open source
- Starting price
- 0 USD
- API
- Available
- Published release
- Prometheus v3.15.0 ↗ (checked )
- Source check
- Primary source ↗ checked
- Website
- prometheus.io ↗
Official resources
What to verify for your environment
Start from the users, systems and operating responsibilities the tool needs to support.
- Confirm current features, licensing and support terms with the publisher.
- Validate deployment, data location, access control, backup and recovery requirements.
- Test integrations, export paths and a representative operational workflow before committing.
ITHub profiles are discovery summaries. Read how product information is presented or report a correction.
Reviews of Prometheus
Rock-solid monitoring for Kubernetes4/5 starsPrometheus with Grafana is the gold standard for Kubernetes monitoring. PromQL takes some getting used to, but once you learn it, the flexibility is unmatched. Alert rules are powerful. The main limitation is long-term storage, which we solve with Thanos.
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