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Fern
API documentation and SDK platform that generates docs, client libraries, and a CLI from an API specification.
API companies that need hosted docs plus generated SDKs in several languages from a single OpenAPI or similar spec.
Teams that only want a Markdown docs site with no SDK generation, or buyers who need every enterprise control on the free tier.
Verdict
Fern is an API documentation and SDK company co-founded by Danny Sheridan and Deep Singhvi, with Sheridan as CEO. Its platform generates documentation sites, client SDKs, and a CLI from an API specification so docs and SDKs stay in sync. Platform teams use it when hand-maintained SDKs become the bottleneck.
Score Breakdown
How Fern scores in the categories that matter to its buyers.
Pricing
Fern publishes a free Docs plan and custom Enterprise pricing.
| Plan | Price | What stands out |
|---|---|---|
| Free | $0 / month | 10 team members, 1,000 pages, 250 AI credits a month |
| Enterprise | Custom | SSO, SCIM, RBAC, multiple repos, self-hosting, SLA |
The Field at a Glance
How Fern compares with other AI developer documentation vendors we reviewed, by Overall Score and relative typical engagement cost.
Fern scores 7.8 in AI developer documentation, under Mintlify (7.9) and ReadMe (7.9), and level with Redocly (7.8). Relative cost lands mid-band for this subcategory.
Use-case matrix
| Use case | Fit | Notes |
|---|---|---|
| Multi-language SDK generation | Strong | One spec ships SDKs across languages. |
| API reference docs | Strong | Docs sites are generated from the same source. |
| Free tier for startups | Strong | Free plan includes custom domain and AI credits. |
| Enterprise security controls | Strong | SSO, SCIM, and self-hosting on Enterprise. |
| Mid-tier self-serve paid plan | Weak | Pricing jumps from Free to custom Enterprise. |
| Markdown-only docs without APIs | Weak | Built around API specs and SDKs. |
Who it’s for
Good fit
- API platform teams
- Developer experience engineers
- Companies maintaining many SDKs
Poor fit
- Markdown-only doc sites
- Buyers needing a mid-tier list price
- Teams without an API spec
Review Excerpts
Below are excerpts from public reviews. Our team scoured public reviews, forums, and chat rooms to get a balanced view of customers' experience with this company. Paid reviews and pay-for-play sites such as Clutch were excluded.
“I used to work at Stripe, where they built their own SDK auto-generation in house. I know how much effort goes into it. It's one of those things that I'm very happy to buy, not build.”
“Adding a feature used to mean implementing it seven times, once per language. Now we change the spec once and it ships in every SDK, so we scale features as fast as we can define them.”
Fern's paid path is a custom Enterprise quote after the Free plan, so teams that outgrow Free have no published mid-tier price to compare before a sales call.
Company Facts
- Founded
- 2022 (CB Insights)
- Headquarters
- New York, New York, United States (CB Insights)
- Employees
- About 30 (Y Combinator)
- Total funding raised
- $9.5M (CB Insights)
- Status
- Acquired by Postman in January 2026 (CB Insights, Fern)
- Key investors
- Postman, Y Combinator, Bessemer Venture Partners, Pioneer Fund, CapitalX (CB Insights)
- Accelerator
- Y Combinator, Winter 2023 batch (Y Combinator)
- Website
- buildwithfern.com
Key Leadership
Danny Sheridan
Co-founder and CEO
Methodology
This page is an independent evaluation of Fern for buyers comparing options in ai developer documentation. AI Industry Reviews accepts no sponsorships, advertising, or pay-for-placement fees. Fern did not pay for this review.
What we scored
The headline number is an Overall Score on a 0-10 scale. Eight criteria sit under it in two groups.
- Buyer outcomes (for ai developer documentation)
- SDK generation
- Docs from API specs
- Spec-driven workflow
- Free-tier enterprise controls
- Company & commercial
- Innovation & product leadership
- Project management & communication
- Pricing
- Contract fairness
Pricing measures whether the price looks fair for the value delivered, including packaging and renewal friction that show up in real buying cycles.
Score Composition
| Input | Weight | What it covers |
|---|---|---|
| Reviews | 40% | A proprietary read of what practitioners say about likes, complaints, and day-to-day use, including public review sites, forums, and private chat rooms. Paid reviews and pay-for-play sites such as Clutch are out of scope. |
| Product | 35% | Hands-on look at screens and workflows. |
| Pricing | 15% | Whether the price looks fair for what you get. |
| Docs & training | 10% | Docs, tutorials, and training material. |
How we balanced the evidence
The Overall Score is the simple average of the eight criteria. Recommendation language follows that score and the fit pattern described above.
Scope
Fern is graded here as ai developer documentation. Criteria scores can move as more review volume and product checks are added.