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APIs · head to head

Formance vs Medius

Formance logo

Formance

APIs

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

From
Free
Rated
-
Full reviewWebsite
Medius logo

Medius

Accounting

Accounts payable automation and supplier payments for mid-market finance teams, Marlin Equity owned

From
On request
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.; Medius the sourcing, contract and procurement modules are considerably less developed than the AP core, so buying Medius as a full source-to-pay suite means accepting weak upstream tooling.
  • They diverge on capability: Formance covers Double-entry ledger, Medius covers Invoice capture and coding.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Formance and Medius actually diverge.

Attributes where Formance and Medius differ
AttributeFormanceMedius
Starting priceFreeOn request
Pricing modelOpen source, no licence feequote
Free tierYesNo
PlatformsLinux, Docker, Kubernetes, Web, APIWeb, iOS, Android
CategoryAPIsAccounting

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 Medius

  • Invoice capture and coding
  • Matching and exception handling
  • Fraud and anomaly detection
  • Supplier payments
  • Approval workflow
  • ERP integration

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

Medius

  • A mid-market finance team where most spend arrives as an invoice with no purchase order to match againstnot Formance
  • A group with several legal entities on different ERPs that wants one AP process across all of themnot Formance
  • Reducing invoice fraud exposure with automated detection of supplier bank detail changesnot Formance
  • Replacing a scanning bureau and a shared AP inbox with automated capture and exception-based reviewnot 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.

Medius

  • The sourcing, contract and procurement modules are considerably less developed than the AP core, so buying Medius as a full source-to-pay suite means accepting weak upstream tooling.
  • Pricing is quote-only and driven by invoice volume, so a business with many low-value invoices pays disproportionately relative to the spend being controlled.
  • Payments are billed on transaction volume separately from the AP subscription, which is easy to omit from a cost comparison against a licence-only AP tool.
  • Private equity ownership since 2017 has produced an acquisition-driven product line, so payments and adjacent capability come from bought-in technology rather than the original platform.
  • ERP integration depth varies sharply by system, and organisations on less common or heavily customised ERPs face integration work that lengthens the implementation.

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

Medius

On request
  • Medius AP Automation$undefined/year
    • Two packaged AP automation tiers
    • Priced by invoice volume and entity count
    • Sourcing, contracts and procurement modules sold separately

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 Medius if

  • You need invoice capture and coding.
  • You work on Web, iOS, Android.
  • You also want matching and exception handling.
Medius review

Questions people ask

Is Formance or Medius better?
Neither clearly leads. Formance starts at Free and Medius at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Formance or Medius?
Formance has a free tier; the other does not. Paid plans start at Free for Formance and On request for Medius.
Does Formance or Medius run on more platforms?
Formance runs on Linux, Docker, Kubernetes, Web, API. Medius runs on Web, iOS, Android.
Can I use Formance for free?
Yes. Formance has a free tier, so you can try it without paying. Medius starts at On request.
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 Medius is typically brought in for.
What can Formance do that Medius cannot?
Formance covers Double-entry ledger, Numscript transaction DSL, Multi-currency, Payments connectivity. Medius covers Invoice capture and coding, Matching and exception handling, Fraud and anomaly detection, Supplier payments.

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.

Medius: Is Medius a procurement suite or an AP tool?

Primarily an AP automation platform with procurement modules attached. If sourcing is your main requirement, look elsewhere.

Formance: Does Formance move money?

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

Medius: Who owns Medius?

Marlin Equity Partners, which acquired it in 2017 and has funded several bolt-on acquisitions since.

Formance: What does the enterprise version cost?

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

Medius: How is it priced?

By quote, driven by invoice volume and entity count, with payments billed separately on transaction volume.

Formance: Do I have to use Numscript?

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

Medius: Does it replace our ERP?

No. It sits alongside the ERP and posts approved invoices into it.

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