DEV.co
Open-Source Observability · cortexproject

cortex

Cortex is a scalable, multi-tenant long-term storage solution for Prometheus metrics. It distributes metrics across a cluster, enables data replication, and stores data in S3, GCS, Azure, or Swift—designed for teams that need to manage metrics at enterprise scale.

Source: GitHub — github.com/cortexproject/cortex
5.8k
GitHub stars
865
Forks
Go
Primary language
Apache-2.0
License (OSI-approved)

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

FieldValue
Repositorycortexproject/cortex
Ownercortexproject
Primary languageGo
LicenseApache-2.0 — OSI-approved
Stars5.8k
Forks865
Open issues313
Latest releasev1.21.1 (2026-06-05)
Last updated2026-07-07
Sourcehttps://github.com/cortexproject/cortex

What cortex is

Written in Go, Cortex horizontally scales by sharding time-series data across multiple nodes using consistent hashing. It implements multi-tenancy via tenant isolation, supports PromQL queries, and integrates with Prometheus and OpenTelemetry Metrics for ingest and retrieval.

Quickstart

Get the cortex source

Clone the repository and explore it locally.

terminalbash
git clone https://github.com/cortexproject/cortex.gitcd cortex# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

Large-scale Prometheus deployments

Organizations managing billions of metrics across multiple clusters or regions benefit from Cortex's horizontal scaling and distributed query execution.

Multi-tenant SaaS monitoring

Service providers offering managed Prometheus can isolate metrics and cost per tenant, with Cortex's multi-tenancy and tenant-aware storage layer.

Long-term metric retention

Cost-effective archival of metrics to object storage (S3, GCS, Azure) with query capability, eliminating single-node storage bottlenecks.

Implementation considerations

  • Requires Kubernetes cluster and reliable object storage backend (S3, GCS, Azure, or Swift); plan for network bandwidth and latency between compute and storage.
  • Multi-component architecture (distributor, ingester, querier, ruler, etc.) demands careful capacity planning, load balancing, and operational monitoring.
  • Configuration is extensive (retention, replication factor, cache layers, ingestion limits); start with documented reference configurations and iterate.
  • Ingest rate limits and multi-tenancy enforcement must be configured per use case; incorrect limits risk data loss or unfair resource sharing.
  • Testing and load modeling are essential before production; Cortex performance depends heavily on cluster topology, storage backend, and query patterns.

When to avoid it — and what to weigh

  • Single-node, simple monitoring — Small deployments with <1M metrics should use vanilla Prometheus or managed services; Cortex's distributed complexity is unnecessary overhead.
  • Real-time alerting only — If you only need immediate alerts (not long-term history), Prometheus alone is simpler and lower-latency; Cortex adds storage and query latency.
  • Unfamiliar with distributed systems — Cortex requires operational experience with Kubernetes, distributed caching (Memcached/Redis), and object storage. Deployment and troubleshooting demand DevOps expertise.
  • Limited storage budget for object storage — Cortex depends on external object storage (S3, GCS, etc.); if you cannot afford long-term cloud storage costs, simpler solutions may fit better.

License & commercial use

Cortex is licensed under Apache License 2.0 (Apache-2.0), a permissive open-source license that allows commercial use, modification, and distribution with proper attribution and liability disclaimers.

Apache-2.0 permits commercial use without royalties. You may build proprietary systems on top of or alongside Cortex. No license review needed for commercial deployment, but you must include the Apache-2.0 license notice in distributions. For legal certainty on integration into larger commercial products, consult your legal team.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

SignalAssessment
MaintenanceActive
DocumentationStrong
License clarityClear
Deployment complexityHigh
DEV.co fitStrong
Assessment confidenceHigh
Security considerations

Security policy and responsible disclosure process documented at https://github.com/cortexproject/cortex/security/policy. Multi-tenancy requires careful tenant isolation configuration; verify authentication (no built-in auth—typically reverse proxy/API gateway) and authorization at ingestion and query boundaries. Data is stored unencrypted in object storage by default; encryption at rest and in transit must be configured separately. Review security guide in documentation before production.

Alternatives to consider

Thanos

Also CNCF/Go-based, uses Prometheus sidecar + S3 for long-term storage. Lighter-weight than Cortex; no multi-tenancy. Better for federated Prometheus deployments; Cortex is better for true multi-tenant SaaS.

Prometheus + object-storage sidecar (e.g., Prometheus operator + snapshot)

Simpler but manual; limited query capability on archived data. Suitable for small-scale archival; does not scale to multi-tenant or real-time global query.

Grafana Loki (for logs) / Grafana Mimir (for metrics)

Mimir is a Cortex fork/successor by Grafana Labs with similar architecture. Choose Mimir if you prefer Grafana-backed support; Cortex remains the community-driven option.

Software development agency

Build on cortex with DEV.co software developers

Cortex is a mature, CNCF-backed solution for enterprise-scale Prometheus deployments. Start with the architecture overview and community Slack if you manage multi-region or SaaS monitoring workloads.

Talk to DEV.co

Related open-source tools

Surfaced by semantic similarity across the DEV.co open-source index.

cortex FAQ

Does Cortex replace Prometheus?
No. Cortex is a long-term storage backend for Prometheus. You still run Prometheus instances (scrapers) and send data to Cortex via remote_write. Cortex handles storage, replication, and queries at scale.
What's the minimum cluster size?
Not specified in data. Cortex is designed for multi-node Kubernetes clusters. Consult architecture docs and KubeCon talks for sizing recommendations based on ingest rate and retention.
Do I need Memcached or Redis?
Not mandatory, but strongly recommended for query performance. Caching accelerates index and chunk lookups; without it, queries are slower and storage I/O increases.
How is data encrypted?
Cortex does not encrypt data at rest by default. Encryption must be configured at the object-storage layer (e.g., S3 SSE, GCS encryption) or via TLS for in-transit. Review security guide.

Software developers & web developers for hire

Adopting cortex is usually one piece of a larger software development effort. As a software development agency, DEV.co provides software development services and web development expertise — pairing senior software developers and web developers with your team to design, build, and operate open-source observability software in production.

Ready to scale your metrics infrastructure?

Cortex is a mature, CNCF-backed solution for enterprise-scale Prometheus deployments. Start with the architecture overview and community Slack if you manage multi-region or SaaS monitoring workloads.