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Fumadocs vs Stainless

Fumadocs logo

Fumadocs

Documentation

Documentation framework for Next.js that treats the docs site as an application rather than a static export

From
Free
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

  • Each has a real cost: Fumadocs it is a library rather than a finished theme, so the initial setup is meaningfully longer than a generator that ships a working site from one command.; Stainless starter and Pro plan prices are not published and require contacting the company.
  • They diverge on capability: Fumadocs covers Next.js App Router native, Stainless covers SDK generation.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Fumadocs and Stainless actually diverge.

Attributes where Fumadocs and Stainless differ
AttributeFumadocsStainless
Pricing modelOpen source, no licence feefreemium
PlatformsWeb, macOS, Windows, Linuxweb, api
CategoryDocumentationAPIs

Identical on both: starting price (Free), free tier (Yes), 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 Fumadocs

  • Next.js App Router native
  • Multiple content sources
  • OpenAPI page generation
  • Built in search
  • Headless and styled layers
  • Type safe frontmatter
  • Code and content colocation

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.

Fumadocs

  • Documentation that must sit behind login and show different content to different customer plansnot Stainless
  • A Next.js product team that wants docs to deploy in the same pipeline as the applicationnot Stainless
  • API reference pages generated from an OpenAPI document alongside hand written guides in one navigation treenot Stainless
  • A design system site where the component documentation must render the live components from the same codebasenot Stainless

Stainless

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

Where each one falls short

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

Fumadocs

  • It is a library rather than a finished theme, so the initial setup is meaningfully longer than a generator that ships a working site from one command.
  • Maintenance is concentrated in a very small group, so an unresponsive week is a blocked upgrade and there is no support contract to escalate to.
  • It only targets Next.js, so adopting it commits the documentation to that framework and a later migration means rewriting the site rather than swapping a theme.
  • Breaking changes have arrived across minor versions during rapid development, so pinning versions and reading migration notes is a recurring cost rather than a one off.
  • Running docs inside the application means docs traffic hits your application infrastructure and shares its failure modes, where a separate static site would have stayed up.

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

Fumadocs

Free
  • Open sourceFree
    • MIT licence
    • All packages included
    • Self hosted or deployed with your Next.js application

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 Fumadocs if

  • You need next.js app router native.
  • You want to start without paying.
  • You work on Web, macOS, Windows, Linux.
  • You also want multiple content sources.
Fumadocs 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 Fumadocs or Stainless better?
Neither clearly leads. Fumadocs starts at Free and Stainless at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Fumadocs or Stainless?
Fumadocs starts at Free and Stainless at Free.
Does Fumadocs or Stainless run on more platforms?
Fumadocs runs on Web, macOS, Windows, Linux. Stainless runs on web, api.
Can I use Fumadocs for free?
Both have a free tier, so you can try either at no cost before committing.
What is Fumadocs best used for?
Fumadocs is most often used for documentation that must sit behind login and show different content to different customer plans, a next.js product team that wants docs to deploy in the same pipeline as the application, api reference pages generated from an openapi document alongside hand written guides in one navigation tree, a design system site where the component documentation must render the live components from the same codebase. Of those, documentation that must sit behind login and show different content to different customer plans and a next.js product team that wants docs to deploy in the same pipeline as the application are not what Stainless is typically brought in for.
What can Fumadocs do that Stainless cannot?
Fumadocs covers Next.js App Router native, Multiple content sources, OpenAPI page generation, Built in search. Stainless covers SDK generation, MCP server generation, Docs site generation, Webhooks and streaming support.

Answered from the vendors’ own pages

Fumadocs: Can I put documentation behind authentication?

Yes. Pages are Next.js server components, so the same session and authorisation checks the rest of the application uses apply.

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
Fumadocs: Does it work outside Next.js?

No. The UI layer depends on the Next.js App Router.

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
Fumadocs: Can it generate pages from an OpenAPI spec?

Yes, including operation pages, schema rendering and an interactive request playground.

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
Fumadocs: Who maintains it and is that a risk?

A very small maintainer group. For a long lived commercial documentation set, treat the low bus factor as a real risk and budget for owning a fork.

Fumadocs: Do I still need a separate docs deployment?

No, and avoiding one is the main reason to choose it. The cost is that docs share your application uptime.

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