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Stainless vs KeystoneJS

Stainless logo

Stainless

Software

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

From
Free
Rated
-
Full reviewWebsite
KeystoneJS logo

KeystoneJS

Software

Powerful Node.js headless CMS framework and API platform

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Stainless starter and Pro plan prices are not published and require contacting the company.; KeystoneJS database support is limited to PostgreSQL, MySQL and SQLite
  • They diverge on capability: Stainless covers SDK generation, KeystoneJS covers REST API.

Where they differ

Only the attributes on which Stainless and KeystoneJS actually diverge.

Attributes where Stainless and KeystoneJS differ
AttributeStainlessKeystoneJS
Pricing modelfreemiumopen-source
Platformsweb, apiNode.js, Self-hosted
FoundedUnknown2016

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Unknown).

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 KeystoneJS

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

What people use each for

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

Stainless

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

KeystoneJS

  • Building a headless CMS with a GraphQL API from a TypeScript schemanot Stainless
  • Generating a configurable Admin UI for editorsnot Stainless
  • Adding structured rich text content with the document fieldnot 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.

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

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

KeystoneJS

Free
  • Open SourceFree
    • Full KeystoneJS
    • Community support

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 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

Questions people ask

Is Stainless or KeystoneJS better?
Neither clearly leads. Stainless starts at Free and KeystoneJS at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Stainless or KeystoneJS?
Stainless starts at Free and KeystoneJS at Free.
Does Stainless or KeystoneJS run on more platforms?
Stainless runs on web, api. KeystoneJS runs on Node.js, Self-hosted.
Can I use Stainless for free?
Both have a free tier, so you can try either at no cost before committing.
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 KeystoneJS is typically brought in for.
What can Stainless do that KeystoneJS cannot?
Stainless covers SDK generation, MCP server generation, Docs site generation, Webhooks and streaming support. KeystoneJS covers REST API, GraphQL API, Admin interface, Node.js.

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
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
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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