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APIs · head to head

Formance vs Mollie

Formance logo

Formance

APIs

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

From
Free
Rated
-
Full reviewWebsite
Mollie logo

Mollie

E-Commerce

European payment service provider with published per-transaction rates and no monthly fee on the online plan

From
£0.3/transaction
Rated
-
Full reviewWebsite

The short version

  • Only Formance has a free tier, so it costs nothing to try first.
  • 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.; Mollie non-European cards cost 3.25% plus 20p against 1.20% plus 20p for UK domestic consumer cards, so a merchant with significant traffic from the US or Asia pays close to triple the domestic rate on that revenue.
  • They diverge on capability: Formance covers Double-entry ledger, Mollie covers Local payment methods.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Formance and Mollie actually diverge.

Attributes where Formance and Mollie differ
AttributeFormanceMollie
Starting priceFree£0.3/transaction
Pricing modelOpen source, no licence feePer transaction by payment method
Free tierYesNo
PlatformsLinux, Docker, Kubernetes, Web, APIWeb, iOS, Android, API
CategoryAPIsE-Commerce

Identical on both: 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 Mollie

  • Local payment methods
  • Published rate card
  • Hosted checkout and payment links
  • Subscriptions API
  • Point of sale terminals
  • Plugin ecosystem
  • Multicurrency settlement

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

Mollie

  • A Dutch or Belgian shop where most customers pay by iDEAL or Bancontact and the flat 30p beats a percentage rate on high-value basketsnot Formance
  • A small merchant that wants published pricing rather than a sales call before it can model card costsnot Formance
  • A subscription business in the EEA collecting by SEPA Direct Debit mandate instead of cardnot Formance
  • A marketplace or platform that needs one integration covering the main European local methodsnot 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.

Mollie

  • Non-European cards cost 3.25% plus 20p against 1.20% plus 20p for UK domestic consumer cards, so a merchant with significant traffic from the US or Asia pays close to triple the domestic rate on that revenue.
  • Coverage is built around European methods, so if you expand into Latin America or Southeast Asia you will need a second processor and a second reconciliation process rather than extending Mollie.
  • The in-person Pro plan requires a one-year contract and charges 20 pounds a month per additional terminal, so a shop with four tills pays 80 pounds a month in terminal fees before any transaction cost.
  • Mollie offers no interchange-plus option publicly, so large merchants cannot see or benefit from falling interchange the way they could on a cost-plus contract with an acquirer.
  • The developer tooling and reporting are lighter than the largest processors, so finance teams that want detailed fee breakdowns or granular reconciliation exports often end up building that layer themselves.

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

Mollie

£0.3/transaction
  • Online paymentsFree
    • No monthly fee
    • UK domestic consumer cards 1.20% + 20p
    • European and commercial cards 2.90% + 20p
  • In person, pay as you goFree
    • No monthly commitment
    • Per-transaction terminal rates
    • One terminal
  • In person, Pro$20/month
    • Lower per-transaction terminal rates
    • One-year contract required
    • Each additional terminal 20 pounds per month

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 Mollie if

  • You need local payment methods.
  • You work on Web, iOS, Android, API.
  • You also want published rate card.
Mollie review

Questions people ask

Is Formance or Mollie better?
Neither clearly leads. Formance starts at Free and Mollie at £0.3/transaction, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Formance or Mollie?
Formance has a free tier; the other does not. Paid plans start at Free for Formance and £0.3/transaction for Mollie.
Does Formance or Mollie run on more platforms?
Formance runs on Linux, Docker, Kubernetes, Web, API. Mollie runs on Web, iOS, Android, API.
Can I use Formance for free?
Yes. Formance has a free tier, so you can try it without paying. Mollie starts at £0.3/transaction.
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 Mollie is typically brought in for.
What can Formance do that Mollie cannot?
Formance covers Double-entry ledger, Numscript transaction DSL, Multi-currency, Payments connectivity. Mollie covers Local payment methods, Published rate card, Hosted checkout and payment links, Subscriptions API.

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.

Mollie: Does Mollie charge a monthly fee?

Not on the online payments plan. You pay only per successful transaction. In-person Pro is 20 pounds a month.

Formance: Does Formance move money?

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

Mollie: Is iDEAL really a flat fee?

Yes, 30p per transaction regardless of the amount, which is why it is cheaper than cards on high-value baskets.

Formance: What does the enterprise version cost?

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

Mollie: Can I use Mollie outside Europe?

You can accept non-European cards but at 3.25% plus 20p, and merchant accounts are aimed at European businesses. It is not a global processor.

Formance: Do I have to use Numscript?

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

Mollie: Does Mollie do interchange plus?

Not publicly. The published rates are blended, so falling interchange does not flow through to you automatically.

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