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APIs · head to head

Formance vs Thunder Client

Formance logo

Formance

APIs

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

From
Free
Rated
-
Full reviewWebsite
Thunder Client logo

Thunder Client

APIs

Lightweight REST API client built as VSCode extension

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.; Thunder Client paid plans are billed annually only: Starter is $3 per user per month and capped at a maximum of 10 seats, Business is $7 per user per month with 500 monthly collection runs per user, and Enterprise is $16 per user per month for unlimited runs
  • They diverge on capability: Formance covers Double-entry ledger, Thunder Client covers REST Client.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Formance and Thunder Client actually diverge.

Attributes where Formance and Thunder Client differ
AttributeFormanceThunder Client
Pricing modelOpen source, no licence feefreemium
PlatformsLinux, Docker, Kubernetes, Web, APIVSCode extension, Web
FoundedUnknown2021

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 Thunder Client

  • REST Client
  • Environment variables
  • Response testing
  • VSCode
  • GitHub
  • Webhook support
  • VSCode extension support
  • 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 Thunder Client
  • A fintech whose homegrown balances table produced numbers finance could not reconcile and now needs proper double-entry before an auditnot Thunder Client
  • A payments team that wants one normalised model across several PSPs so reconciliation is not written separately for eachnot Thunder Client
  • A company that wants its ledger under a licence it can keep running even if the vendor disappearsnot Thunder Client

Thunder Client

  • 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.

Thunder Client

  • Paid plans are billed annually only: Starter is $3 per user per month and capped at a maximum of 10 seats, Business is $7 per user per month with 500 monthly collection runs per user, and Enterprise is $16 per user per month for unlimited runs

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

Thunder Client

Free
  • FreeFree
    • REST client
    • Collection management
    • Local testing
  • Pro$8/monthly
    • Cloud sync
    • Team collaboration
    • Advanced features

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 Thunder Client if

  • You need rest client.
  • You want to start without paying.
  • You work on VSCode extension, Web.
  • You also want environment variables.
Thunder Client review

Questions people ask

Is Formance or Thunder Client better?
Neither clearly leads. Formance starts at Free and Thunder Client at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Formance or Thunder Client?
Formance starts at Free and Thunder Client at Free.
Does Formance or Thunder Client run on more platforms?
Formance runs on Linux, Docker, Kubernetes, Web, API. Thunder Client runs on VSCode extension, Web.
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 Thunder Client is typically brought in for.
What can Formance do that Thunder Client cannot?
Formance covers Double-entry ledger, Numscript transaction DSL, Multi-currency, Payments connectivity. Thunder Client covers REST Client, Environment variables, Response testing, VSCode.

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.

Thunder Client: How much does Thunder Client cost?

Thunder Client publishes a free plan at no cost, then Starter at $3, Business at $7 and Enterprise at $16, all priced annually.

Source
Formance: Does Formance move money?

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

Thunder Client: Is Thunder Client free?

Yes, there is a free plan. It is used through the Thunder Client extension for VS Code, available from the marketplace, with limits applied compared with the paid tiers.

Source
Formance: What does the enterprise version cost?

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

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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