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Cybersecurity · head to head

Ory Kratos vs Thanos

Ory Kratos logo

Ory Kratos

Cybersecurity

Headless identity and user management API

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: Ory Kratos headless means you build every screen, which is significant work compared with a hosted login page; Thanos several components — sidecar, store, querier, compactor, ruler — each with its own configuration and failure modes
  • They diverge on capability: Ory Kratos covers Headless API, Thanos covers Global query.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Ory Kratos and Thanos actually diverge.

Attributes where Ory Kratos and Thanos differ
AttributeOry KratosThanos
Pricing modelOpen-source self-hosted, with a paid managed networkOpen source, no licence fee
PlatformsLinux, Docker, Kubernetes, Self-hostedKubernetes, Linux, Docker
CategoryCybersecurityCloud

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 Ory Kratos

  • Headless API
  • Self-service flows
  • Multi-factor authentication
  • Pluggable identity schemas

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.

Ory Kratos

  • Products needing complete control over the look and flow of authenticationnot Thanos
  • Applications that must not hand user identity data to a third partynot Thanos
  • Teams building identity as infrastructure across several servicesnot Thanos

Thanos

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

Where each one falls short

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

Ory Kratos

  • Headless means you build every screen, which is significant work compared with a hosted login page
  • More moving parts than a monolithic IAM: Kratos handles identity, and OAuth2 needs Ory Hydra alongside
  • Documentation assumes real familiarity with identity concepts and is not a gentle introduction
  • Self-hosting identity carries the security and availability burden that hosted providers absorb

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

Ory Kratos

Free
  • Self-hostedFree
    • Full identity server
    • All flows
    • Community support

Thanos

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

Which should you pick?

Choose Ory Kratos if

  • You need headless api.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Self-hosted.
  • You also want self-service flows.
Ory Kratos 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 Ory Kratos or Thanos better?
Neither clearly leads. Ory Kratos 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, Ory Kratos or Thanos?
Ory Kratos starts at Free and Thanos at Free.
Does Ory Kratos or Thanos run on more platforms?
Ory Kratos runs on Linux, Docker, Kubernetes, Self-hosted. Thanos runs on Kubernetes, Linux, Docker.
Can I use Ory Kratos for free?
Both have a free tier, so you can try either at no cost before committing.
What is Ory Kratos best used for?
Ory Kratos is most often used for products needing complete control over the look and flow of authentication, applications that must not hand user identity data to a third party, teams building identity as infrastructure across several services. Of those, products needing complete control over the look and flow of authentication and applications that must not hand user identity data to a third party are not what Thanos is typically brought in for.
What can Ory Kratos do that Thanos cannot?
Ory Kratos covers Headless API, Self-service flows, Multi-factor authentication, Pluggable identity schemas. Thanos covers Global query, Object storage retention, Deduplication, Downsampling.

Answered from the vendors’ own pages

Ory Kratos: Is Ory Kratos free?

Yes, open source and free to self-host. Ory Network is a paid managed service.

Thanos: Is Thanos free?

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

Ory Kratos: What does headless mean here?

Kratos provides identity flows as APIs and no user interface. You build the login, registration and recovery screens yourself.

Thanos: Does Thanos replace Prometheus?

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

Ory Kratos: Does Kratos do OAuth2?

No. Kratos handles user identity; OAuth2 and OpenID Connect provider functionality is Ory Hydra, a separate component.

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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