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APIs · head to head

KeystoneJS vs Solaris

KeystoneJS logo

KeystoneJS

APIs

Powerful Node.js headless CMS framework and API platform

From
Free
Rated
-
Full reviewWebsite
Solaris logo

Solaris

APIs

German banking as a service with a full banking licence and a live regulatory problem

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only KeystoneJS has a free tier, so it costs nothing to try first.
  • Each has a real cost: KeystoneJS database support is limited to PostgreSQL, MySQL and SQLite; Solaris baFin appointed a special representative in 2022 and extended the mandate in July 2024, so a partner is joining a bank under active supervisory monitoring, with slower approvals and heavier compliance demands as a direct consequence.
  • They diverge on capability: KeystoneJS covers REST API, Solaris covers German banking licence.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which KeystoneJS and Solaris actually diverge.

Attributes where KeystoneJS and Solaris differ
AttributeKeystoneJSSolaris
Starting priceFreeOn request
Pricing modelopen-sourcequote
Free tierYesNo
PlatformsNode.js, Self-hostedWeb, API
Founded2016Unknown

Identical on both: 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 KeystoneJS

  • REST API
  • GraphQL API
  • Admin interface
  • Node.js
  • Next.js
  • React
  • Databases
  • Node.js support

Only in Solaris

  • German banking licence
  • IBAN accounts
  • Card issuing
  • Lending as a service
  • Digital assets and custody
  • SEPA payments
  • KYC and onboarding
  • Deposit protection

What people use each for

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

KeystoneJS

  • Headless CMS implementationnot Solaris
  • Content management systemsnot Solaris
  • Customizable API-driven applicationsnot Solaris

Solaris

  • A retailer or platform launching a German current account or card product without applying for its own licencenot KeystoneJS
  • A fintech that needs deposit taking and lending, which an e-money licence cannot providenot KeystoneJS
  • A European business needing German IBANs because customers reject foreign IBANs for salary and direct debitnot KeystoneJS
  • A company requiring German statutory deposit protection on customer balances as a product claimnot KeystoneJS

Where each one falls short

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

KeystoneJS

  • Database support is limited to PostgreSQL, MySQL and SQLite
  • Keystone 5 is a separate legacy product documented on a different site and is not covered by the Keystone 6 docs
  • Upgrading requires following a dedicated Migrate to 8.0.0 guide, so major versions are not drop-in
  • Free support is a community Slack; enterprise-grade consulting and support is a separate paid engagement with Thinkmill and no published price

Solaris

  • BaFin appointed a special representative in 2022 and extended the mandate in July 2024, so a partner is joining a bank under active supervisory monitoring, with slower approvals and heavier compliance demands as a direct consequence.
  • BaFin fined Solaris EUR 6.5 million in March 2024 for systematically late suspicious activity reports and EUR 500,000 for breaching large exposure limits between January 2022 and March 2024, which is a track record a partner inherits reputationally.
  • Solaris has previously needed BaFin approval before onboarding new corporate clients, which can turn a commercial decision to launch into a regulatory timetable outside your control.
  • The 2024 restructuring involved job cuts and the closure of parts of a business unit, so product lines a partner depends on may not have the engineering behind them that the sales process implies.
  • SBI Holdings acquired majority control in 2025, so strategic direction now sits with a Japanese financial group whose priorities for the European business may differ from the roadmap you were sold.

Pricing, plan by plan

KeystoneJS

Free
  • Open SourceFree
    • Full KeystoneJS
    • Community support

Solaris

On request
  • Solaris banking as a service$undefined/year
    • Quoted per partner, typically setup fee plus monthly platform fee
    • Per account, per card and per transaction charges on top
    • Interchange sharing arrangements negotiated per programme

Which should you pick?

Choose KeystoneJS if

  • You need rest api.
  • You want to start without paying.
  • You work on Node.js, Self-hosted.
  • You also want graphql api.
KeystoneJS review

Choose Solaris if

  • You need german banking licence.
  • You work on Web, API.
  • You also want iban accounts.
Solaris review

Questions people ask

Is KeystoneJS or Solaris better?
Neither clearly leads. KeystoneJS starts at Free and Solaris at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, KeystoneJS or Solaris?
KeystoneJS has a free tier; the other does not. Paid plans start at Free for KeystoneJS and On request for Solaris.
Does KeystoneJS or Solaris run on more platforms?
KeystoneJS runs on Node.js, Self-hosted. Solaris runs on Web, API.
Can I use KeystoneJS for free?
Yes. KeystoneJS has a free tier, so you can try it without paying. Solaris starts at On request.
What is KeystoneJS best used for?
KeystoneJS is most often used for headless cms implementation, content management systems, customizable api-driven applications. Of those, headless cms implementation and content management systems are not what Solaris is typically brought in for.
What can KeystoneJS do that Solaris cannot?
KeystoneJS covers REST API, GraphQL API, Admin interface, Node.js. Solaris covers German banking licence, IBAN accounts, Card issuing, Lending as a service.

Answered from the vendors’ own pages

KeystoneJS: Is KeystoneJS free?

Yes, KeystoneJS is free and open source with no licensing fees. Core platform has no lock-in and is contributed to by 250+ developers.

Source
Solaris: Does Solaris have a real banking licence?

Yes. Solaris SE is a German credit institution, which is why it can offer deposits and lending, unlike e-money based competitors.

KeystoneJS: What are hosting costs for KeystoneJS?

KeystoneJS is self-hosted and deployment-agnostic. Hosting costs depend on your chosen deployment platform (Vercel, AWS, Heroku, etc.) and infrastructure, not KeystoneJS itself.

Source
Solaris: Is the BaFin action still live?

The special representative appointed in 2022 had the mandate extended in July 2024, and fines were issued in March 2024. Treat supervisory oversight as an active condition in your diligence.

KeystoneJS: Does KeystoneJS offer paid support?

Enterprise support with tailored options is available from Thinkmill, the company behind KeystoneJS. Pricing details available upon request.

Source
Solaris: Who owns Solaris now?

SBI Holdings of Japan agreed in December 2024 and January 2025 to take a majority stake of over seventy per cent for around EUR 100 million.

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