Fern

Fern is a documentation and SDK-generation platform for teams building APIs. It suits developers who want interactive API references alongside strongly typed client libraries. Its appeal is breadth; its main caveat is that several advanced capabilities sit behind custom-priced Enterprise.

Overview

Fern turns Markdown and API specifications into documentation websites, with API references generated from OpenAPI, AsyncAPI, gRPC, and other specifications. It also generates client libraries with IDE support, schema validation, and idiomatic method names. That combination makes Fern a strong fit when docs and SDKs need to be managed together, rather than a simple choice for teams seeking only a general-purpose knowledge base.

Key features

Documentation includes an API Explorer, web editor, changelog pages, version and product switching, and localization. These features give teams ways to present and maintain API material for different products and audiences without limiting the site to static reference pages.

AI features include search, a writing agent, translations, and an MCP server. The Free plan supplies 250 AI credits per month, so its AI allowance is useful for measured use, not an unlimited workflow. Listed integrations include PostHog, Google Analytics, Segment, Mixpanel, FullStory, Intercom, Postman, and Context7.

Access controls include password protection, SSO, JWT, OAuth, and role-based access control. Fern's trust center lists SOC 2 Type II, GDPR, and CCPA, and provides access requests for its SOC 2 report, penetration test summary, and information security policy. Custom domains, version history, and content analytics are also supported.

Pricing

Plan	Price	What it includes
Free	free; billed Free forever	10 team members, 1,000 pages, 250 AI credits per month, 2,000 page generations per month, and 1 site
Enterprise	Custom pricing	SSO, SCIM, and advanced RBAC; multiple repos and docs instances; advanced analytics and data exports; dedicated infrastructure with self-hosting available; uptime SLA and dedicated support

The Free plan's generous team allowance makes it practical for a small team evaluating or maintaining one site, but its page, generation, and AI quotas set clear ceilings. Enterprise is aimed at organizations needing multiple documentation instances, stronger access administration, dedicated infrastructure, or contractual support and uptime commitments. There is no paid middle tier in these plans, so teams that outgrow Free will need to consider a custom-priced Enterprise arrangement.

Platforms

Fern supports API, Linux, macOS, self-hosted, web, and Windows environments. Its CLI generator compiles signed binaries for macOS, Linux, and Windows. Self-hosting is an Enterprise capability, so it is not part of the Free plan's deployment options.

Who it's for

Fern is best suited to API teams that want interactive documentation, SDK generation, and access controls in one platform. The Free plan can serve smaller teams with a single site and usage within its quotas. Organizations that need self-hosting, multiple docs instances, SCIM, advanced analytics exports, or dedicated support should expect an Enterprise conversation. It is less compelling for teams that need only lightweight process documentation rather than API-focused docs and SDKs.

Pros and cons

• Pros: One platform covers interactive API references and strongly typed SDK generation, with support for several API specification formats.
• Pros: The Free plan includes 10 team members and meaningful monthly page-generation and AI-credit allowances, plus a custom domain and one site.
• Pros: Password, SSO, JWT, OAuth, and role-based controls support both public and restricted documentation use cases.
• Cons: Free is capped at one site, 1,000 pages, and 2,000 monthly page generations, which may constrain larger or high-traffic documentation projects.
• Cons: Self-hosting, multiple instances, SCIM, advanced analytics exports, and dedicated support require custom-priced Enterprise.
• Cons: AI use is bounded by 250 credits per month on Free, limiting its fit for teams that expect sustained AI-assisted writing or translation.

Alternatives

Mintlify is worth considering for teams seeking a similar documentation platform with a free Starter plan that includes five editor seats, a custom domain, web editor, authentication, MCP server, and API playground; its Pro plan is 450.00, so compare its seat allowance and paid-tier cost against Fern's free quotas and Enterprise needs.

Tango is a better fit for capturing and sharing browser workflows: its free plan supports five shared workflows, browser capture, link and embed sharing, and up to 10 users per workspace.

GitBook may suit an individual who wants a free documentation site, unlimited page views, and 10 GitBook Agent messages per week; its free plan includes one user.

Scribe is an alternative documentation tool.

AutomaDocs may suit a developer seeking repository-based AI documentation: its free plan includes one repository, 50 AI chat messages per month, core doc generation, GitHub integration, and auto-sync on push.

Documentation.AI is another freemium documentation option.

InkLoom may appeal to teams prioritizing unlimited pages and one free user per project, with a free subdomain and community support.

CodeDocs AI is a freemium alternative for code documentation.

For category comparisons, explore AI Documentation Generators, Technical Documentation Software, API Documentation Tools, Developer Documentation Software, Code Generators, and Knowledge base software.

Verdict

Choose Fern if your team wants API documentation and SDK generation together, with a free plan broad enough to start a single-site project and access controls for restricted docs. Look elsewhere if you need self-hosting or larger-scale administrative features without moving to custom-priced Enterprise, or if your documentation needs are not centered on APIs.