Cortex vs Prometheus
A side-by-side comparison of two self-hosted monitoring & status options — licensing, setup difficulty, resource needs, and what each one replaces.
Prometheus
Metrics-based monitoring and alerting toolkit
| Feature | Cortex | Prometheus |
|---|---|---|
| Deploy effort | Under-an-hour setup | ≈5-minute setup |
| Health score | 90 · Excellent | 100 · Excellent |
| Category | Monitoring & Status | Monitoring & Status |
| License | Apache-2.0 | Apache-2.0 |
| Language | Go | Go |
| Setup difficulty | Hard | Medium |
| Min. RAM | 1,024 MB | 512 MB |
| Deployment | docker, kubernetes, helm | docker, binary, helm |
| GitHub stars | ★ 5,865 | ★ 66,196 |
| First released | 2016 | 2015 |
| Replaces | Datadog, Grafana Cloud | Datadog |
What are Cortex and Prometheus?
Cortex
Cortex provides a horizontally scalable, highly available, multi-tenant, long-term store for Prometheus metrics. It offers a single API endpoint for querying and writing time series data across clusters.
- Multi-tenant metrics storage
- Horizontally scalable
- Prometheus-compatible API
- Long-term retention
Prometheus
Prometheus is a metrics-based monitoring system and time-series database with a powerful query language and alerting. It targets engineers monitoring cloud-native infrastructure. It is deployed via Docker, binaries, or Helm.
- Pull-based metrics collection
- PromQL query language
- Built-in alerting rules
- Cloud-native standard
Cortex vs Prometheus: key differences
Both projects are written in Go. Prometheus is the lighter option, starting around 512 MB of RAM against 1,024 MB for Cortex. Prometheus has the considerably larger community, at 66,196 GitHub stars versus 5,865.
Why pick each one
Choose Cortex if…
- Built for very large scale
- True multi-tenancy
Watch out for
- Operationally heavy
- Overkill for small setups
Choose Prometheus if…
- Powerful query language
- Reliable and scalable
- Huge ecosystem
Watch out for
- No long-term storage by default
- Dashboards need Grafana
Frequently asked questions
Is Cortex or Prometheus better?
Prometheus is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider Cortex if its specific feature set fits your needs better.
Are Cortex and Prometheus free and open-source?
Yes. Cortex is licensed under Apache-2.0 and Prometheus under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Cortex and Prometheus with Docker?
Cortex: yes. Prometheus: yes.
Which is lighter on resources, Cortex or Prometheus?
Prometheus has the smaller minimum footprint at 512 MB of RAM, compared to about 1,024 MB for Cortex. Real-world usage depends on library size, user count, and enabled features.