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APIs · head to head

Formance vs Swagger/OpenAPI

Formance logo

Formance

APIs

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

From
Free
Rated
-
Full reviewWebsite
Swagger/OpenAPI logo

Swagger/OpenAPI

APIs

API specification and documentation framework using OpenAPI standard

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.; Swagger/OpenAPI the OpenAPI Specification itself is licensed under Apache License 2.0 and free to use; SwaggerHub is a separate paid tool built on top of it
  • They diverge on capability: Formance covers Double-entry ledger, Swagger/OpenAPI covers OpenAPI Specification.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Formance and Swagger/OpenAPI actually diverge.

Attributes where Formance and Swagger/OpenAPI differ
AttributeFormanceSwagger/OpenAPI
Pricing modelOpen source, no licence feefreemium
PlatformsLinux, Docker, Kubernetes, Web, APIWeb, CLI, Desktop
FoundedUnknown2001

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

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 Swagger/OpenAPI

  • OpenAPI Specification
  • Interactive Documentation
  • Code Generation
  • GitHub
  • GitLab
  • Jenkins
  • IDE plugins
  • Web support

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 Swagger/OpenAPI
  • A fintech whose homegrown balances table produced numbers finance could not reconcile and now needs proper double-entry before an auditnot Swagger/OpenAPI
  • A payments team that wants one normalised model across several PSPs so reconciliation is not written separately for eachnot Swagger/OpenAPI
  • A company that wants its ledger under a licence it can keep running even if the vendor disappearsnot Swagger/OpenAPI

Swagger/OpenAPI

  • API Developmentnot Formance
  • API Gatewaynot Formance
  • API Testingnot Formance
  • API Documentationnot Formance
  • Microservicesnot 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.

Swagger/OpenAPI

  • The OpenAPI Specification itself is licensed under Apache License 2.0 and free to use; SwaggerHub is a separate paid tool built on top of it

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

Swagger/OpenAPI

Free
  • Open SourceFree
    • OpenAPI specification
    • Community tools
  • SwaggerHub FreeFree
    • Cloud editor
    • API mocking
    • API testing
  • SwaggerHub Pro$75/monthly
    • Team collaboration
    • Advanced mocking
    • Analytics

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 Swagger/OpenAPI if

  • You need openapi specification.
  • You want to start without paying.
  • You work on Web, CLI, Desktop.
  • You also want interactive documentation.
Swagger/OpenAPI review

Questions people ask

Is Formance or Swagger/OpenAPI better?
Neither clearly leads. Formance starts at Free and Swagger/OpenAPI at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Formance or Swagger/OpenAPI?
Formance starts at Free and Swagger/OpenAPI at Free.
Does Formance or Swagger/OpenAPI run on more platforms?
Formance runs on Linux, Docker, Kubernetes, Web, API. Swagger/OpenAPI runs on Web, CLI, Desktop.
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 Swagger/OpenAPI is typically brought in for.
What can Formance do that Swagger/OpenAPI cannot?
Formance covers Double-entry ledger, Numscript transaction DSL, Multi-currency, Payments connectivity. Swagger/OpenAPI covers OpenAPI Specification, Interactive Documentation, Code Generation, GitHub.

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.

Swagger/OpenAPI: Is Swagger UI free to use?

Swagger UI is an open source tool with source code publicly available on GitHub at no cost. It is one of thousands of free open source projects in the Swagger ecosystem.

Source
Formance: Does Formance move money?

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

Swagger/OpenAPI: What commercial Swagger products are available beyond the open source tools?

Swagger offers Swagger for Teams for streamlined API workflow with interactive editors and hosted documentation, and Swagger Enterprise for organizations needing secure on-premise or cloud-based environments. Specific pricing requires contacting sales.

Source
Formance: What does the enterprise version cost?

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

Swagger/OpenAPI: Are there commercial versions that build on the open source Swagger tools?

Yes, commercial Swagger products integrate the core functionality of Swagger open source tools (Editor, UI, and Codegen) with advanced capabilities for team collaboration, standards enforcement, and enterprise features.

Source
Formance: Do I have to use Numscript?

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

Swagger/OpenAPI: Is there a trial available for Swagger commercial products?

A Start Trial call-to-action is available on the Swagger website, but specific trial duration and terms are not disclosed on the product pages.

Source
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