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APIs · head to head

Aiia vs Stainless

Aiia logo

Aiia

APIs

Open banking and open finance API platform, now operating as Mastercard Open Banking

From
On request
Rated
-
Full reviewWebsite
Stainless logo

Stainless

APIs

Generates client SDKs, API docs, and MCP servers from an OpenAPI spec

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Stainless has a free tier, so it costs nothing to try first.
  • Each has a real cost: Aiia it is now part of Mastercard rather than an independent company, so a business specifically wanting to avoid card network dependency in its banking infrastructure no longer gets that separation by choosing Aiia.; Stainless starter and Pro plan prices are not published and require contacting the company.
  • They diverge on capability: Aiia covers Bank account data access, Stainless covers SDK generation.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Aiia and Stainless actually diverge.

Attributes where Aiia and Stainless differ
AttributeAiiaStainless
Starting priceOn requestFree
Pricing modelquotefreemium
Free tierNoYes

Identical on both: platforms (Web, API), 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 Aiia

  • Bank account data access
  • Payment initiation
  • Mastercard Open Finance integration
  • Modern authentication support
  • Multi-country coverage
  • Developer documentation and sandbox

Only in Stainless

  • SDK generation
  • MCP server generation
  • Docs site generation
  • Webhooks and streaming support
  • Automated unit tests
  • Git integration

What people use each for

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

Aiia

  • A lending or credit product needing affordability checks via European bank account datanot Stainless
  • A personal finance or accounting product needing transaction history across Nordic and European banksnot Stainless
  • A payments product wanting account-to-account payment initiation under open banking regulationnot Stainless
  • A business wanting the stability and continued investment of Mastercard ownership behind its banking connectivity providernot Stainless

Stainless

  • Generating typed SDKs for a public APInot Aiia
  • Producing an MCP server from an existing OpenAPI specnot Aiia
  • Building an API documentation site alongside client librariesnot Aiia
  • Giving open-source APIs a free SDK generation pathnot Aiia

Where each one falls short

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

Aiia

  • It is now part of Mastercard rather than an independent company, so a business specifically wanting to avoid card network dependency in its banking infrastructure no longer gets that separation by choosing Aiia.
  • Pricing is not published and requires engaging Mastercard's open finance sales process, which can be a heavier sales motion than dealing with a smaller independent open banking provider.
  • Its strongest bank coverage remains concentrated in the Nordics and Northern Europe, so companies needing dense coverage in Southern or Eastern Europe should verify current bank connectivity before committing.
  • Brand confusion is real: developer documentation, login portals and older case studies still reference "Aiia" while newer Mastercard material refers to "Mastercard Open Banking," and a company researching either name in isolation may miss half the relevant material.
  • As with any open banking platform, reliability still depends on the consistency of the underlying banks' own APIs, which is a systemic industry issue rather than something Aiia specifically controls.

Stainless

  • Starter and Pro plan prices are not published and require contacting the company.
  • The free plan caps APIs at 25 endpoints, which excludes larger production APIs.
  • Overage charges apply per SDK/endpoint/month once limits are exceeded, which can make costs unpredictable at scale.

Pricing, plan by plan

Aiia

On request
  • Aiia Enterprise (Mastercard Open Banking)$undefined/year
    • Pricing not published, quote via Mastercard Open Finance sales

Stainless

Free
  • FreeFree
    • Up to 5 generators (SDKs, docs, or MCP servers)
    • 5 seats
    • APIs with 25 or fewer endpoints
  • Starter$undefined/mo
    • Unlimited generators
    • Expanded seats
    • Private SDKs of any size
  • Pro$undefined/mo
    • Custom enterprise features and pricing
  • Enterprise$undefined/mo
    • Dedicated support
    • SOC 2 compliance reports
    • Purchase order/invoicing with negotiable terms

Which should you pick?

Choose Aiia if

  • You need bank account data access.
  • You work on Web, API.
  • You also want payment initiation.
Aiia review

Choose Stainless if

  • You need sdk generation.
  • You want to start without paying.
  • You work on web, api.
  • You also want mcp server generation.
Stainless review

Questions people ask

Is Aiia or Stainless better?
Neither clearly leads. Aiia starts at On request and Stainless at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Aiia or Stainless?
Stainless has a free tier; the other does not. Paid plans start at On request for Aiia and Free for Stainless.
Does Aiia or Stainless run on more platforms?
Aiia runs on Web, API. Stainless runs on web, api.
Can I use Stainless for free?
Yes. Stainless has a free tier, so you can try it without paying. Aiia starts at On request.
What is Aiia best used for?
Aiia is most often used for a lending or credit product needing affordability checks via european bank account data, a personal finance or accounting product needing transaction history across nordic and european banks, a payments product wanting account-to-account payment initiation under open banking regulation, a business wanting the stability and continued investment of mastercard ownership behind its banking connectivity provider. Of those, a lending or credit product needing affordability checks via european bank account data and a personal finance or accounting product needing transaction history across nordic and european banks are not what Stainless is typically brought in for.
What can Aiia do that Stainless cannot?
Aiia covers Bank account data access, Payment initiation, Mastercard Open Finance integration, Modern authentication support. Stainless covers SDK generation, MCP server generation, Docs site generation, Webhooks and streaming support.

Answered from the vendors’ own pages

Aiia: Is Aiia still an independent company?

No, it was acquired by Mastercard in 2021 and now operates as part of Mastercard Open Finance Solutions, referenced as Aiia Enterprise.

Stainless: Is there a free plan, and what are its limits?

Yes. The Free plan supports up to 5 generators, 5 seats, APIs with 25 or fewer endpoints, and 100 preview builds per month, with email support.

Source
Aiia: Does the Aiia brand still exist?

Yes, in developer documentation and login portals, but the company behind it is Mastercard.

Stainless: Who owns the generated SDK code?

The generated SDK code is owned by the customer and published by Stainless under the Apache 2.0 license.

Source
Aiia: Which banks does it cover?

Around 3,000 European banks, with strongest coverage in the Nordics and Northern Europe.

Stainless: What happens if I exceed my plan's endpoint limit?

Customers exceeding their endpoint limits are billed per SDK, per endpoint, per month for the overage.

Source
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