Instant Docs and SDKs for your API
Start with an API spec. Generate SDKs in multiple languages and interactive API documentation tailored to your brand. Support for REST (OpenAPI), WebSockets (AsyncAPI), and gRPC (Protobuf) APIs.
Fern's docs-as-code approach lets teams write documentation in Markdown, version changes in Git, review via pull requests, and use Fern Writer (a Slack-based AI agent) to draft updates. This integrates documentation workflows into existing development processes without requiring dedicated technical writing headcount.
Fern's Enterprise plan offers multi-source docs aggregation, role-based access control (RBAC), SSO/SAML integration, self-hosting options, SOC 2 Type II compliance, and dedicated support. This enables large organizations to manage documentation for dozens of APIs and services from a single platform with security and compliance controls.
Fern serves documentation as clean Markdown with auto-generated llms.txt files, MCP servers, and Ask Fern AI chat. This enables coding assistants, agents, and LLMs to reliably read and execute your API without hallucinations, with built-in support for Claude, Cursor, and other AI tools.
Fern automatically generates beautiful, customizable documentation websites and client libraries in multiple languages from OpenAPI, GraphQL, AsyncAPI, or gRPC specs. This eliminates manual documentation maintenance and ensures SDKs stay synchronized with your API definition, reducing time to first API call by 99% according to their metrics.
Fern provides interactive API explorers, auto-populated API keys for instant testing, built-in AI search (Ask Fern), and agent-ready documentation. These features reduce support burden by $1.3M+ annually for customers and accelerate developer onboarding by providing instant answers grounded in your actual documentation.