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Networking · head to head

Prometheus vs Thanos

Prometheus logo

Prometheus

Networking

Open source monitoring and alerting toolkit for cloud native environments

From
Free
Rated
-
Full reviewWebsite
Thanos logo

Thanos

Cloud

Highly available Prometheus with long-term object storage

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Prometheus not suitable for per-request billing as collected data lacks 100% accuracy; Thanos several components — sidecar, store, querier, compactor, ruler — each with its own configuration and failure modes
  • They diverge on capability: Prometheus covers Multi-dimensional Data Model, Thanos covers Global query.

Where they differ

Only the attributes on which Prometheus and Thanos actually diverge.

Attributes where Prometheus and Thanos differ
AttributePrometheusThanos
Pricing modelopen-sourceOpen source, no licence fee
PlatformsLinux, macOS, WindowsKubernetes, Linux, Docker
CategoryNetworkingCloud
Founded2015Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Prometheus

  • Multi-dimensional Data Model
  • PromQL Query Language
  • Pull-based Collection
  • Service Discovery
  • Alerting Rules
  • Federation
  • Local Storage
  • Grafana

Only in Thanos

  • Global query
  • Object storage retention
  • Deduplication
  • Downsampling

What people use each for

The jobs each tool is most often brought in to do.

Prometheus

  • Monitoring and alerting systemnot Thanos
  • Time-series databasenot Thanos
  • Infrastructure metrics collectionnot Thanos

Thanos

  • Querying metrics across many clusters or regions from one placenot Prometheus
  • Retaining metrics for years without local disk growthnot Prometheus
  • Removing the gap that appears when a single Prometheus instance restartsnot Prometheus

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Prometheus

  • Not suitable for per-request billing as collected data lacks 100% accuracy
  • Hard limit on scrape body size; large responses cause scrape failure
  • Per-scrape sample limit enforced; exceeding limit marks targets as failed
  • Not designed for long-term durable storage; optimised for metrics collection

Thanos

  • Several components — sidecar, store, querier, compactor, ruler — each with its own configuration and failure modes
  • The compactor is a common source of operational trouble and must not run twice against the same bucket
  • Query latency over object storage is meaningfully higher than local Prometheus
  • Object storage costs and API request charges become real at high volume

Pricing, plan by plan

Prometheus

Free
  • Prometheus (Open Source)Free
    • 100% open source
    • Community-driven project
    • Apache 2 License

Thanos

Free
  • ThanosFree
    • Full functionality
    • No usage limits
    • Community support

Which should you pick?

Choose Prometheus if

  • You need multi-dimensional data model.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want promql query language.
Prometheus review

Choose Thanos if

  • You need global query.
  • You want to start without paying.
  • You work on Kubernetes, Linux, Docker.
  • You also want object storage retention.
Thanos review

Questions people ask

Is Prometheus or Thanos better?
Neither clearly leads. Prometheus starts at Free and Thanos at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Prometheus or Thanos?
Prometheus starts at Free and Thanos at Free.
Does Prometheus or Thanos run on more platforms?
Prometheus runs on Linux, macOS, Windows. Thanos runs on Kubernetes, Linux, Docker.
Can I use Prometheus for free?
Both have a free tier, so you can try either at no cost before committing.
What is Prometheus best used for?
Prometheus is most often used for monitoring and alerting system, time-series database, infrastructure metrics collection. Of those, monitoring and alerting system and time-series database are not what Thanos is typically brought in for.
What can Prometheus do that Thanos cannot?
Prometheus covers Multi-dimensional Data Model, PromQL Query Language, Pull-based Collection, Service Discovery. Thanos covers Global query, Object storage retention, Deduplication, Downsampling.

Answered from the vendors’ own pages

Prometheus: What does Prometheus cost?

Prometheus is completely free and open source. There are no pricing tiers or paid plans. The entire project is licensed under Apache 2 and hosted on GitHub.

Source
Thanos: Is Thanos free?

Yes, open source and CNCF-incubating. Costs are the object storage it uses.

Prometheus: Is Prometheus commercial software or free?

Prometheus is 100% open source and community-driven. It is a CNCF graduated project with no commercial restrictions or licensing fees.

Source
Thanos: Does Thanos replace Prometheus?

No. It runs alongside existing Prometheus servers, adding global query, deduplication and long-term storage.

Prometheus: How is Prometheus licensed?

Prometheus is licensed under the Apache 2 License, which permits free use, modification, and distribution for commercial and non-commercial purposes.

Source
Thanos: Thanos or VictoriaMetrics?

Thanos layers onto Prometheus using object storage and is the more established multi-cluster answer. VictoriaMetrics is a separate store aiming at lower resource use and fewer moving parts.

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