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Cortex vs etcd

Cortex logo

Cortex

Developer Tools

Internal developer portal that scores service ownership and maturity rather than just cataloguing services

From
On request
Free plan
No
etcd logo

etcd

Technology

A distributed key-value store using Raft consensus, built for cluster coordination rather than application data.

From
On request
Free plan
No

The short version

  • Each has a real cost: Cortex pricing is quote only, so a platform team cannot build a business case or compare against the true cost of self-hosted Backstage without entering a sales cycle first.; etcd it is sized for coordination data, not application data: the default backend quota is 2 GB and 8 GB is the documented recommended maximum, and exceeding it puts the cluster into a NOSPACE alarm where it accepts no writes until an operator compacts, defragments and clears the alarm by hand.
  • They diverge on capability: Cortex covers Service catalogue, etcd covers Raft consensus.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cortex and etcd actually diverge.

Attributes where Cortex and etcd differ
AttributeCortexetcd
Pricing modelquoteopen-source
PlatformsWeb, APIWeb
CategoryDeveloper ToolsTechnology

Identical on both: starting price (On request), free tier (No), 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 Cortex

  • Service catalogue
  • Scorecards
  • Initiatives
  • Self-service templates
  • Query language
  • Eng intelligence
  • Integrations layer
  • On-call and ownership mapping

Only in etcd

  • Raft consensus
  • Linearizable reads
  • Transactions
  • Leases
  • Watches
  • MVCC revision history
  • Role-based access control
  • Snapshot backup and restore

What people use each for

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

Cortex

  • A platform team that needs to prove to leadership how far a Kubernetes or framework migration has actually progressed across hundreds of servicesnot etcd
  • An organisation where ownership of production services is genuinely unknown after reorganisations or acquisitionsnot etcd
  • Enforcing production readiness standards on new services at creation time rather than at incident reviewnot etcd
  • Replacing a self-hosted Backstage that is consuming a full-time engineer or two just to stay upgradednot etcd

etcd

  • Storing Kubernetes cluster state, which is what the overwhelming majority of etcd deployments are doingnot Cortex
  • Leader election and distributed locking in a home-grown scheduler or control plane, using leases and transactionsnot Cortex
  • Service discovery and dynamic configuration where readers need to be notified of changes rather than poll for themnot Cortex
  • Coordinating failover in a clustered database, as Patroni does for PostgreSQLnot Cortex

Where each one falls short

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

Cortex

  • Pricing is quote only, so a platform team cannot build a business case or compare against the true cost of self-hosted Backstage without entering a sales cycle first.
  • The catalogue is only as accurate as the metadata you supply, so an organisation with inconsistent repository conventions spends its first quarter cleaning data before any scorecard means anything.
  • Scorecards create political friction: publishing a per-team grade turns an engineering standard into a performance metric, and teams will game the rules rather than fix the underlying issue.
  • It is closed source and hosted, so organisations with strict data residency or air-gap requirements have limited options compared with running Backstage themselves.
  • Value scales with organisation size, so a company with fifty engineers and thirty services will find the catalogue tells them nothing they did not already know while still paying an enterprise contract.

etcd

  • It is sized for coordination data, not application data: the default backend quota is 2 GB and 8 GB is the documented recommended maximum, and exceeding it puts the cluster into a NOSPACE alarm where it accepts no writes until an operator compacts, defragments and clears the alarm by hand.
  • Every write is replicated and fsynced before acknowledgement, so cluster performance is bounded by the slowest disk in it; a member on network-attached storage with high fsync latency causes leader elections and cluster-wide latency spikes that look like network problems and are not.
  • Adding members increases availability but reduces write throughput, because each write must reach a larger quorum; you run three or five members for fault tolerance, and increasing capacity means faster hardware rather than more nodes.
  • There is no sharding and no multi-tenancy, so isolating workloads means running separate clusters, each with its own quorum, certificates, backup schedule and upgrade path, and that operational multiplication is often unexpected.
  • Running it yourself is a real job: periodic compaction and defragmentation, snapshot backups you have actually rehearsed restoring, and rotation of both peer and client TLS certificates, none of which happens automatically outside a managed Kubernetes service.
  • Losing quorum is not self-healing; recovering a cluster that has lost a majority means restoring from a snapshot and accepting that everything written since that snapshot is gone, which makes backup frequency a data-loss budget decision rather than a routine setting.

Pricing, plan by plan

Cortex

On request
  • Cortex$undefined/year
    • Service catalogue and ownership mapping
    • Scorecards and initiatives
    • Self-service templates

etcd

On request

No published plan breakdown. See the etcd review.

Which should you pick?

Choose Cortex if

  • You need service catalogue.
  • You work on Web, API.
  • You also want scorecards.

Choose etcd if

  • You need raft consensus.
  • You also want linearizable reads.

Questions people ask

Is Cortex or etcd better?
Neither clearly leads. Cortex starts at On request and etcd at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cortex or etcd?
Cortex starts at On request and etcd at On request.
Does Cortex or etcd run on more platforms?
Cortex runs on Web, API. etcd runs on Web.
What is Cortex best used for?
Cortex is most often used for a platform team that needs to prove to leadership how far a kubernetes or framework migration has actually progressed across hundreds of services, an organisation where ownership of production services is genuinely unknown after reorganisations or acquisitions, enforcing production readiness standards on new services at creation time rather than at incident review, replacing a self-hosted backstage that is consuming a full-time engineer or two just to stay upgraded. Of those, a platform team that needs to prove to leadership how far a kubernetes or framework migration has actually progressed across hundreds of services and an organisation where ownership of production services is genuinely unknown after reorganisations or acquisitions are not what etcd is typically brought in for.
What can Cortex do that etcd cannot?
Cortex covers Service catalogue, Scorecards, Initiatives, Self-service templates. etcd covers Raft consensus, Linearizable reads, Transactions, Leases.

Answered from the vendors’ own pages

Cortex: How is Cortex different from Backstage?

Backstage is an open source framework you build and staff. Cortex is a hosted product with scorecards and initiatives out of the box and no platform team required to keep it running.

etcd: Can I use etcd as an application database?

No. It is designed for metadata and coordination, with a recommended maximum store size of around 8 GB, no sharding and a write path deliberately optimised for durability rather than throughput. Application data belongs in a database built for it.

Cortex: Is pricing published?

No. Cortex requires a sales conversation and prepares a custom proposal.

etcd: How many members should a cluster have?

Three for most cases, five where you need to survive two simultaneous failures. Always an odd number, because an even-sized cluster gains no additional fault tolerance while making quorum harder to reach.

Cortex: Can it self-host?

It is offered as a hosted product; on-premise arrangements are handled through sales rather than published.

etcd: What happens when the store fills up?

The cluster raises a NOSPACE alarm and stops accepting writes, becoming effectively read-only. Recovery requires compacting old revisions, defragmenting each member and then explicitly disarming the alarm, all done by an operator.

Cortex: What is the main adoption risk?

Bad or missing service metadata. The catalogue and every scorecard on top of it inherit whatever quality your repositories already have.

etcd: Why is my etcd cluster slow or unstable?

Almost always disk latency. Because every write is fsynced before acknowledgement, slow or shared storage causes heartbeat timeouts, leader elections and cascading latency. Local SSDs with low fsync latency are effectively a requirement.

etcd: How does it compare with Consul or ZooKeeper?

All three provide consensus-backed coordination. etcd has the simplest data model and the Kubernetes ecosystem behind it; Consul bundles service discovery, health checking and a service mesh; ZooKeeper is older, JVM-based and still common under Kafka and Hadoop-era systems.

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