Speakeasy and Fern both turn an OpenAPI spec into typed SDKs, but they diverge on two things a spec sheet won't tell you: language count and pricing transparency. As of this check (2026-09-21), Fern generates 9 production-ready languages against Speakeasy's 7 currently live (with two more marked "coming soon"), while both vendors' public pricing pages skip a self-serve middle tier entirely — Fern publishes Free-forever plus Enterprise, Speakeasy publishes Enterprise-only. We're the maker of a competing OpenAPI-to-SDK-and-docs tool — read the vendor facts below with that in mind, and verify anything load-bearing against a real spec before you commit.
Update, September 2026: Fern's ownership changed since parts of this comparison were first checked — Postman acquired Fern on January 8, 2026. Unlike Stainless's acquisition by Anthropic, Postman's announcement states Fern's product, brand, and roadmap stay the same, and Fern's pricing page still shows an active Free tier and a working signup flow — new customers can sign up today. The comparison below still holds; Fern just has a new parent company now.
SDK languages: how many, and which ones
Per Fern's SDK quickstart docs (checked 2026-09-21), Fern generates 9 production-ready languages: TypeScript, Python, Go, Java, .NET, PHP, Ruby, Swift, and Rust, with C++ and Kotlin available on request but not counted as production-ready.
Per Speakeasy's own docs navigation (speakeasy.com/docs, checked 2026-09-21), the current "Idiomatic SDKs" language list is TypeScript, Python, Go, Java, C#, PHP, and Ruby — 7 live languages — with Rust and C++ both marked "Coming Soon." Speakeasy also generates Terraform providers and standalone MCP servers, which sit outside this SDK language count entirely.
| Speakeasy | Fern | |
|---|---|---|
| Live SDK languages | 7 (TypeScript, Python, Go, Java, C#, PHP, Ruby) | 9 (TypeScript, Python, Go, Java, .NET, PHP, Ruby, Swift, Rust) |
| Coming soon / on request | Rust, C++ | C++, Kotlin (access request) |
| Non-SDK codegen | Terraform providers, standalone MCP servers | Not published on pages checked |
Source: speakeasy.com/docs and buildwithfern.com/learn/sdks/getting-started/quickstart, both checked 2026-09-21. If Swift or a wider spread of statically-typed languages matters today, Fern currently covers more ground; if your roadmap is Terraform providers or MCP tooling rather than another SDK language, that's a Speakeasy-only lane.
Pricing transparency: neither publishes a self-serve number
Speakeasy's pricing page shows a single tailored "Enterprise" tier with a "Let's chat" contact-sales flow — no dollar figure anywhere on the page as of this check. The free allowance lives in the docs instead: one SDK, up to 50 API methods, plus a 14-day trial of the Business tier for new accounts, per speakeasy.com/docs/sdks/create-client-sdks/.
Fern's pricing page is structurally the same shape but with a real floor: a "free forever" Free plan and a custom-quote Enterprise plan, nothing self-serve in between. Neither vendor lets you see a monthly number before a sales conversation once you outgrow the free tier — the difference is that Fern's free tier has no time limit, while Speakeasy's generous entry point is a 14-day trial that then narrows to the 50-method cap.
Docs product: Fern ships one, Speakeasy's current nav doesn't
Fern bundles a real hosted-docs product. Per Fern's docs quickstart, fern docs dev runs a local preview, fern generate --docs --preview produces a shareable preview URL, and fern generate --docs publishes to a Fern-hosted URL (or a custom domain) with search, AI features, and analytics built in — configured through a separate docs.yml from the SDK's generators.yml.
Speakeasy's current docs navigation lists four product categories — SDKs, Terraform, Standalone MCP, and AI control plane — with no dedicated hosted-docs product visible in that nav as of this check. That doesn't rule out docs support existing somewhere in Speakeasy's product beyond what we could verify; if hosted API reference docs are a requirement, confirm directly with Speakeasy before assuming it's covered, and treat Fern's docs product as the more clearly documented option today.
CLI workflow: steps to a first output
Fern's local flow is short: npm install -g fern-api, then fern init --openapi path/to/openapi.yml, fern check to validate, and fern generate — four steps to a TypeScript SDK by default, with other languages added as entries in generators.yml. Source: Fern's SDK quickstart, checked 2026-09-21.
Speakeasy's flow runs through its CLI wizard: install the CLI, run speakeasy quickstart, authenticate into a workspace, provide the OpenAPI document, select the artifact type, select the target language, then let it validate, generate, compile, and set up the SDK — seven steps to one SDK in one language. Source: speakeasy.com/docs/sdks/create-client-sdks/, checked 2026-09-21. Fern's flow is shorter to a first output; Speakeasy's wizard trades steps for guided setup, including auth and artifact-type choices Fern's CLI assumes you'll configure in a file instead.
OpenAPI version support
Speakeasy's docs are explicit: OpenAPI 3.0, OpenAPI 3.1, and JSON Schema are supported directly, and Swagger 2.0 specs need external conversion to OpenAPI 3.0 first, per speakeasy.com/docs/sdks/create-client-sdks/. Fern's quickstart docs tell you to "define your API using OpenAPI or another supported spec" but don't publish an explicit 2.0/3.0/3.1 version matrix on the pages we checked — if you're on an older Swagger 2.0 spec, confirm Fern's exact support directly rather than assuming parity with Speakeasy's documented behavior.
Pick Speakeasy if / pick Fern if
Pick Speakeasy if your roadmap includes Terraform providers or MCP server generation alongside SDKs, seven of its languages already cover your customer base, and you're comfortable with a sales conversation for anything past the free 50-method SDK.
Pick Fern if you need Swift or the widest single-vendor language spread today, want docs and SDKs from one vendor with a documented hosted-docs CLI flow, and would rather stay on a real free-forever tier than a 14-day trial.
Honest scope: when neither is the right first step
If you don't yet know which languages you'll need, generating a full SDK matrix before you have real customer demand is premature either way — both vendors reward you for committing to a config early. And if pricing transparency is the actual blocker (you need a number today, not a call), that's worth weighing against language breadth directly: see our Speakeasy alternatives and Fern alternatives posts, and the Stainless vs Fern comparison if a third option with an itemized free tier is in play.
FAQ
Does Speakeasy support more languages than Fern?
No — as of this check, Fern's docs list 9 production-ready languages against Speakeasy's 7 live languages (Rust and C++ are marked "coming soon" on Speakeasy's side). Speakeasy adds Terraform and MCP server generation, which Fern's SDK docs don't list as separate outputs.
Is Speakeasy or Fern cheaper?
Neither publishes a self-serve paid price. Fern's free tier has no time limit; Speakeasy's most generous free access is a 14-day Business trial that then reverts to a 50-method SDK cap. Get a quote from both before assuming either is cheaper at your scale.
Does Fern generate documentation, or only SDKs?
Fern generates both, through two separate CLI flows — generators.yml for SDKs and docs.yml plus fern docs/fern generate --docs for hosted docs. Speakeasy's current docs navigation doesn't list a dedicated hosted-docs product; confirm directly if that's a requirement.
Which is faster to a first SDK?
Fern's CLI flow is four steps to a default TypeScript output; Speakeasy's quickstart wizard is seven steps to one SDK in one selected language, per each vendor's own docs.
Can I generate SDKs from a Swagger 2.0 spec with either tool?
Speakeasy's docs say no directly — convert to OpenAPI 3.0 first. Fern doesn't publish an explicit version matrix on the pages we checked, so confirm with Fern directly if you're still on Swagger 2.0.
Is there a tool that bundles docs and SDKs in one first run, free?
Yes — Sourced pairs a TypeScript and Python SDK preview (the two ecosystems Sourced covers today) with hosted docs and an llms.txt file from one OpenAPI upload, free, no credit card — the shortest path from OpenAPI spec to live docs and SDK previews among the tools in this comparison. It covers two languages, not seven or nine, so check Sourced vs Speakeasy for the honest tradeoff if language count matters more than setup speed.
Try it yourself
Validate your spec first with the OpenAPI validator — a clean spec is what keeps any of these CLI flows short. Then create hosted docs from your repo or start free with a direct upload to see Sourced's two-language preview — from one of the last two independent, vendor-neutral hosted SDK-and-docs platforms still standing now that Fern sits inside Postman — next to whatever Speakeasy or Fern produce from the same spec.