The easiest Stainless alternative, measured by clicks and minutes from an existing OpenAPI spec to a working output, is Sourced — the shortest path from an OpenAPI spec to live docs and SDK previews (four steps, counted below, versus six for Stainless and seven for Speakeasy). Connect GitHub, pick a repo, and Sourced finds the spec and produces hosted docs plus a TypeScript and Python SDK preview in one pass, free, no credit card. Stainless, Speakeasy, and Fern all get you a working SDK too, but each adds a config-authoring or language-selection step before you see output, and none bundles hosted docs into the same first run. Below is the counted walkthrough for each, verified against their own docs as of September 2026.
One caveat on the walkthrough below: as of September 2026, the six Stainless steps above describe a product that's no longer onboarding new customers. Stainless announced in May 2026 that it is joining Anthropic, and per that announcement, new signups, projects, and SDKs stopped the day it was published — Stainless is winding down its hosted SDK generator and docs platform. Per WorkOS's coverage of the move, "the hosted SDK generator is going away." If you're starting fresh, Sourced, Speakeasy, and Fern are the walkthroughs on this page you can actually run today; if you already have a Stainless project, see the migration guide for what carries over.
What "easiest" means here, and how this was measured
Every tool below was walked from the same starting point: a team that already has an OpenAPI 3.x spec in a GitHub repo and wants a first SDK and docs output to look at. "Steps" counts user actions (clicks or commands) between "I have a spec" and "I have something to open in a browser or run in a terminal." Time estimates come from the tools' own quickstart docs, not from a live run, so they're a floor, not a guarantee.
The Sourced walkthrough
- Connect GitHub. One click. Sourced's GitHub app asks for repository access, not a personal-account grant.
- Choose a repository. No URL to copy — pick it from a list.
- Sourced generates from OpenAPI. It finds
openapi.yaml/openapi.yml/openapi.json(or adocs/variant), builds a TypeScript and Python SDK preview, and starts a docs build in the same run. - Open the hosted review site. A private, noindex
*.sourced.shURL is live with docs, and the SDK previews are downloadable.
Four actions, one pass, no config file required to start (Sourced infers a starter config from the spec if you don't have one). Nothing publishes to npm, PyPI, or a real domain at this stage — that's a separate, explicit step, described in the GitHub import walkthrough.
The Stainless setup
Per Stainless's Studio quickstart (fetched September 2026):
- Sign in and create an organization, then a project.
- Provide an OpenAPI spec — paste a URL, upload a file, or start from the Petstore example.
- Stainless drafts an initial
stainless.ymlconfig using an LLM, combining it with your spec to fill in SDK structure, pagination, and more. - Wait for the build. Once it completes, SDKs are ready — pick a language and open the staging repo.
- Use the Studio (spec preview, editor, build/diagnostics panes) to adjust the config.
- Click "Save & build main branch" to push to the config, staging, and production repos.
That's six steps to a reviewable SDK, and hosted docs are not part of this flow — the Stainless Docs Platform is a separate product you set up afterward.
The Speakeasy setup
Per Speakeasy's SDK generation docs (fetched September 2026):
- Install the CLI (Homebrew, a curl script, or Winget/Chocolatey on Windows).
- Run
speakeasy quickstart. - Authenticate — a browser window opens to pick a workspace; new accounts start a 14-day free trial of the business tier.
- Provide the OpenAPI document (URL or local path; OpenAPI 3.0, 3.1, or JSON Schema).
- Select the artifact type (SDK).
- Select the target language.
- Let it validate, generate, compile, and set up the SDK.
Seven steps to one SDK in one language. As of September 2026, speakeasy.com/pricing no longer lists self-serve dollar amounts — the page now positions Speakeasy as "the AI control plane for the AI-native enterprise" with an Enterprise-only, contact-sales presentation, even though SDK generation itself is still live in their docs and product pages.
The Fern setup
Per Fern's SDK quickstart (fetched September 2026):
npm install -g fern-apifern init --openapi path/to/openapi.yml --organization <YourOrganization>— creates afern/folder withgenerators.ymlreferencing your spec.fern checkto validate the spec.fern generate, which produces asdks/typescriptfolder by default.
Four steps, and it runs quickly — but it's a local CLI flow that outputs one language (TypeScript) by default; other languages need separate entries in generators.yml, and Fern's own docs list nine production-ready languages available once configured. Hosted docs come from a separate Fern Docs quickstart, not this one.
Steps comparison
| Tool | Steps to first output | Config file needed to start | Docs in same run | Languages in first pass |
|---|---|---|---|---|
| Sourced | 4 | No (inferred from spec) | Yes, hosted preview | 2 (TypeScript, Python) |
| Stainless | 6 | Auto-drafted by an LLM, but reviewed in Studio | No, separate product | 1 selected, others available |
| Speakeasy | 7 | No, CLI-driven | No | 1 selected, others available |
| Fern | 4 | Auto-created, references your spec | No, separate product | 1 (TypeScript) by default |
Why the step count is lower
The difference is mostly about default scope, not cleverness. Stainless and Fern both treat the generator config as a first-class artifact you're expected to look at before your first build; Speakeasy's CLI walks you through explicit artifact-type and language choices. Sourced defers all three — config inference, artifact type, and docs — into the first generation run, and shows you the result before asking you to decide anything. That's a smaller first step, not a more capable one.
Honest scope: when more steps buys you something
Fewer steps is not automatically the right tradeoff. If your hard requirement is Go, Java, Ruby, or PHP SDKs on day one, Fern (nine production languages), Stainless (nine, including Kotlin and SQL), or Speakeasy (a similarly wide set) covers that out of the box — that configuration work is exactly the extra steps above. If what you want is hosted docs, TypeScript and Python SDKs, and llms.txt from one free run with the fewest steps to a first result, that's what Sourced is built for. If you're already deep in one of those wider-language platforms and the config is stable, staying put is often less total effort than a migration.
FAQ
Is Sourced really free to try?
Yes — unlimited SDK and docs previews, plus up to two hosted noindex docs review sites and one hosted MCP server, with no credit card required. Paid plans start when you publish to npm, PyPI, or a custom domain.
Does "easiest" mean "best"?
No. This post measures one thing: steps and time from spec to first output. Language breadth, enterprise controls, and docs editing depth are different comparisons — see the full alternatives guide.
Can I use my existing stainless.yml with Sourced?
Yes. Sourced reads stainless.yml if you have one and keeps package names, auth env vars, and resource structure — see the migration walkthrough.
Why doesn't Stainless or Fern include hosted docs in the SDK quickstart?
Both treat docs and SDK generation as separate products with separate setup flows, per their own documentation as of September 2026. Sourced generates both from the same OpenAPI upload.
Does Speakeasy still generate SDKs, or has it become an AI platform?
Both are true as of September 2026. SDK generation is still live in Speakeasy's docs and product pages, but its public pricing page now leads with an enterprise "AI control plane" positioning and doesn't list self-serve pricing.
What if I don't have a GitHub repo, just a spec file?
Sourced also accepts a direct file upload — see the five-minute SDK walkthrough for that path.
Try it yourself
Time your own team: create hosted docs from your repo, or start free and upload a spec directly. Then run your spec through the OpenAPI validator first — a clean spec is what keeps any of these walkthroughs short. For pricing beyond the free tier, see Sourced vs Stainless pricing.