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APIs · head to head

Stainless vs Treasury Prime

Stainless logo

Stainless

APIs

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

From
Free
Rated
-
Full reviewWebsite
Treasury Prime logo

Treasury Prime

APIs

Banking as a service platform sold to sponsor banks rather than to fintechs

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Stainless has a free tier, so it costs nothing to try first.
  • Each has a real cost: Stainless starter and Pro plan prices are not published and require contacting the company.; Treasury Prime a fintech cannot buy Treasury Prime directly since the 2024 pivot, so the sales process starts with finding a sponsor bank willing to take your programme, which adds months and removes most of your negotiating leverage on fees.
  • They diverge on capability: Stainless covers SDK generation, Treasury Prime covers BankOS.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Stainless and Treasury Prime actually diverge.

Attributes where Stainless and Treasury Prime differ
AttributeStainlessTreasury Prime
Starting priceFreeOn request
Pricing modelfreemiumquote
Free tierYesNo
Platformsweb, apiAPI, Web

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 Stainless

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

Only in Treasury Prime

  • BankOS
  • OneKey Banking
  • Deposit accounts
  • Payments
  • Card issuing
  • Bank oversight tooling
  • Ledger and reconciliation
  • Programme onboarding

What people use each for

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

Stainless

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

Treasury Prime

  • A community or regional bank that wants to run an embedded finance line with examiner-acceptable oversight of its fintech programmesnot Stainless
  • A fintech that has already chosen its sponsor bank and needs API access to that bank rather than to a middleware layernot Stainless
  • A company that wants deposits spread across several banks for FDIC coverage beyond a single institution limitnot Stainless
  • A bank replacing a fragile middleware arrangement with a structure where it holds the customer contract and the oversight obligationnot Stainless

Where each one falls short

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

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.

Treasury Prime

  • A fintech cannot buy Treasury Prime directly since the 2024 pivot, so the sales process starts with finding a sponsor bank willing to take your programme, which adds months and removes most of your negotiating leverage on fees.
  • Commercial terms including minimum deposit balances, reserve requirements and per transaction pricing are set by the bank rather than the platform, so two fintechs on the same software can face materially different economics with no public benchmark.
  • The company cut roughly half its staff in the 2024 pivot, which reduced the teams that supported fintech customers directly and left fintechs relying on their bank for support rather than on the vendor who wrote the software.
  • Bank risk appetite is now the binding constraint, and after the Synapse failure sponsor banks decline programmes in higher risk categories that a middleware provider would once have onboarded, so some business models simply cannot get placed.
  • If your sponsor bank exits the programme or is told by its regulator to reduce fintech exposure, you are migrating your entire deposit base to another institution, and the software being the same at both ends does not make that a small project.

Pricing, plan by plan

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

Treasury Prime

On request
  • BankOS$undefined/year
    • Sold to sponsor banks, not directly to fintechs
    • Fintech commercial terms are set by the sponsor bank
    • Minimum deposits, reserves and per transaction fees vary by bank

Which should you pick?

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

Choose Treasury Prime if

  • You need bankos.
  • You work on API, Web.
  • You also want onekey banking.
Treasury Prime review

Questions people ask

Is Stainless or Treasury Prime better?
Neither clearly leads. Stainless starts at Free and Treasury Prime at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Stainless or Treasury Prime?
Stainless has a free tier; the other does not. Paid plans start at Free for Stainless and On request for Treasury Prime.
Does Stainless or Treasury Prime run on more platforms?
Stainless runs on web, api. Treasury Prime runs on API, Web.
Can I use Stainless for free?
Yes. Stainless has a free tier, so you can try it without paying. Treasury Prime starts at On request.
What is Stainless best used for?
Stainless is most often used for generating typed sdks for a public api, producing an mcp server from an existing openapi spec, building an api documentation site alongside client libraries, giving open-source apis a free sdk generation path. Of those, generating typed sdks for a public api and producing an mcp server from an existing openapi spec are not what Treasury Prime is typically brought in for.
What can Stainless do that Treasury Prime cannot?
Stainless covers SDK generation, MCP server generation, Docs site generation, Webhooks and streaming support. Treasury Prime covers BankOS, OneKey Banking, Deposit accounts, Payments.

Answered from the vendors’ own pages

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
Treasury Prime: Can a fintech buy Treasury Prime directly?

No. Since the 2024 pivot it sells to banks. A fintech contracts with a sponsor bank running BankOS, and the bank sets the terms.

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
Treasury Prime: Why did it change model?

Regulatory pressure on the tri-party middleware structure, sharpened by the Synapse failure. Examiners want the bank holding the customer contract and the oversight obligation, which is what bank-direct means.

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
Treasury Prime: What is OneKey Banking?

A way of spreading deposits across several banks in the network, used for FDIC coverage above a single institution limit and for resilience if one bank exits.

Treasury Prime: Is pricing published?

No, at neither the bank nor the fintech level. Fintech economics are set by the sponsor bank, so expect wide variation.

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