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APIs · head to head

Formance vs Rook

Formance logo

Formance

APIs

Open source double-entry ledger and payment orchestration for money-moving software

From
Free
Rated
-
Full reviewWebsite
Rook logo

Rook

Cloud

Kubernetes operator that deploys and manages Ceph storage clusters

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Formance formance holds no money and provides no regulatory cover, so it must be paired with a payments provider or bank, and buyers occasionally mistake a ledger for a treasury system and discover the gap late.; Rook rook automates Ceph but does not abstract it, so an incident still demands Ceph expertise, and organisations without it end up hiring consultants at exactly the wrong moment.
  • They diverge on capability: Formance covers Double-entry ledger, Rook covers Ceph operator.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Formance and Rook actually diverge.

Attributes where Formance and Rook differ
AttributeFormanceRook
PlatformsLinux, Docker, Kubernetes, Web, APILinux, Kubernetes
CategoryAPIsCloud

Identical on both: starting price (Free), pricing model (Open source, no licence fee), 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 Formance

  • Double-entry ledger
  • Numscript transaction DSL
  • Multi-currency
  • Payments connectivity
  • Reconciliation
  • Self-hosted deployment
  • Cloud offering
  • API and SDKs

Only in Rook

  • Ceph operator
  • Block, file and object
  • Erasure coding
  • CSI driver
  • Automated upgrades
  • Multi-cluster mirroring

What people use each for

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

Formance

  • A marketplace splitting a single customer payment between seller, platform fee and tax that needs the split to be atomic and auditablenot Rook
  • A fintech whose homegrown balances table produced numbers finance could not reconcile and now needs proper double-entry before an auditnot Rook
  • A payments team that wants one normalised model across several PSPs so reconciliation is not written separately for eachnot Rook
  • A company that wants its ledger under a licence it can keep running even if the vendor disappearsnot Rook

Rook

  • An on-premises Kubernetes platform needing block, shared filesystem and S3 storage without buying three productsnot Formance
  • A team that already runs Ceph and wants its lifecycle managed declaratively inside Kubernetesnot Formance
  • A large cluster where three-way replication overhead is unaffordable and erasure coding is requirednot Formance
  • An organisation building a private cloud that cannot use managed cloud storage services for residency reasonsnot Formance

Where each one falls short

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

Formance

  • Formance holds no money and provides no regulatory cover, so it must be paired with a payments provider or bank, and buyers occasionally mistake a ledger for a treasury system and discover the gap late.
  • Numscript is a domain-specific language your team must learn, and while it makes complex splits expressible it also means transaction logic sits outside the languages your engineers already debug well.
  • Self-hosting a ledger that must never lose or duplicate a transaction is a serious operational commitment covering backups, upgrades and Postgres tuning, which is real cost the zero licence fee hides.
  • Enterprise pricing is not published, so the difference between the free path and the supported path cannot be evaluated without a sales conversation.
  • The company is much smaller than the incumbent alternatives, and while the MIT licence protects the code it does not protect the roadmap, so features on the hosted side may arrive slowly or change direction.

Rook

  • Rook automates Ceph but does not abstract it, so an incident still demands Ceph expertise, and organisations without it end up hiring consultants at exactly the wrong moment.
  • There is no vendor and no SLA; the realistic commercial support routes are IBM Red Hat OpenShift Data Foundation or an independent Ceph consultancy, both of which change the cost picture entirely.
  • Ceph is resource hungry, needing substantial memory and dedicated disks per OSD, so the hardware cost of a properly sized cluster is often underestimated.
  • Recovery and rebalancing after a disk or node failure generates heavy background input and output that can degrade application performance for hours, which surprises teams sizing for steady state.
  • Minimum viable clusters require several nodes with several disks each, so it is impractical at small scale and the entry hardware cost exceeds simpler alternatives.

Pricing, plan by plan

Formance

Free
  • Open SourceFree
    • MIT licensed core ledger
    • Numscript transaction DSL
    • Multi-currency tracking
  • Enterprise$undefined/year
    • Managed or private deployment
    • Payments connectivity and reconciliation
    • Support with response commitments

Rook

Free
  • RookFree
    • Apache 2.0 licensed, no licence fee
    • Graduated CNCF project
    • Community support via GitHub and Slack only

Which should you pick?

Choose Formance if

  • You need double-entry ledger.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Web, API.
  • You also want numscript transaction dsl.
Formance review

Choose Rook if

  • You need ceph operator.
  • You want to start without paying.
  • You work on Linux, Kubernetes.
  • You also want block, file and object.
Rook review

Questions people ask

Is Formance or Rook better?
Neither clearly leads. Formance starts at Free and Rook at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Formance or Rook?
Formance starts at Free and Rook at Free.
Does Formance or Rook run on more platforms?
Formance runs on Linux, Docker, Kubernetes, Web, API. Rook runs on Linux, Kubernetes.
Can I use Formance for free?
Both have a free tier, so you can try either at no cost before committing.
What is Formance best used for?
Formance is most often used for a marketplace splitting a single customer payment between seller, platform fee and tax that needs the split to be atomic and auditable, a fintech whose homegrown balances table produced numbers finance could not reconcile and now needs proper double-entry before an audit, a payments team that wants one normalised model across several psps so reconciliation is not written separately for each, a company that wants its ledger under a licence it can keep running even if the vendor disappears. Of those, a marketplace splitting a single customer payment between seller, platform fee and tax that needs the split to be atomic and auditable and a fintech whose homegrown balances table produced numbers finance could not reconcile and now needs proper double-entry before an audit are not what Rook is typically brought in for.
What can Formance do that Rook cannot?
Formance covers Double-entry ledger, Numscript transaction DSL, Multi-currency, Payments connectivity. Rook covers Ceph operator, Block, file and object, Erasure coding, CSI driver.

Answered from the vendors’ own pages

Formance: Is Formance really open source?

Yes. The core ledger is MIT licensed with full source access and no deployment restrictions.

Rook: Who supports it in production?

Nobody by default. IBM sells Red Hat OpenShift Data Foundation, which is supported Rook and Ceph, and independent consultancies sell Ceph support. Decide this before deployment.

Formance: Does Formance move money?

No. It records and orchestrates movements; the actual payments happen at a PSP or bank you connect.

Rook: Does it need Ceph knowledge?

Yes. Rook handles deployment and routine operations, but troubleshooting a degraded cluster is a Ceph skill and there is no way around it.

Formance: What does the enterprise version cost?

Not published. It is an annual subscription quoted per customer.

Rook: Can it replace an object storage appliance?

Functionally yes, through the RADOS gateway, but you take on the operations that an appliance vendor would otherwise carry.

Formance: Do I have to use Numscript?

Yes for anything beyond the simplest transfers. It is how multi-party transactions are expressed atomically.

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